How do we know who is right? Because I don't see it this way. When Mrs. White spoke of "definite time," she was contrasting what happened in 1844 with what would not happen again--an exact date proclaimed for Jesus' Second Coming. I see the "definite time" as a reference to a precise date for this event. I do not see it as precluding all prophetic events, nor even of erasing all precise times.

It appears you are reading the paragraph above as if Ellen was writing chronologically. You seem to be saying Jesus doesn't leave the sanctuary until “after” the plagues are poured out. However, if the following passages describe the same event, namely, Jesus leaving the sanctuary, isn't it clear the plagues fall after Jesus leaves the sanctuary?

Let all our brethren and sisters beware of anyone who would set a time for the Lord to fulfill His word in regard to His coming, or in regard to any other promise He has made of special significance. "It is not for you to know the times or the seasons, which the Father hath put in His own power." False teachers may appear to be very zealous for the work of God, and may expend means to bring their theories before the world and the church; but as they mingle error with truth, their message is one of deception, and will lead souls into false paths. They are to be met and opposed, not because they are bad men, but because they are teachers of falsehood and are endeavoring to put upon falsehood the stamp of truth. {TM 55.1}

The preaching of definite time called forth great opposition from all classes, from the minister in the pulpit down to the most reckless, heaven-daring sinner. "No man knoweth the day nor the hour," was heard from the hypocritical minister and the bold scoffer. Neither would be instructed and corrected by those who were pointing to the year when they believed the prophetic periods would run out, and to the signs which showed Christ near, even at the doors. Many shepherds of the flock, who professed to love Jesus, said that they had no opposition to the preaching of Christ's coming, but they objected to the definite time. God's all-seeing eye read their hearts. They did not love Jesus near. They knew that their unchristian lives would not stand the test, for they were not walking in the humble path marked out by Him. These false shepherds stood in the way of the work of God. The truth spoken in its convincing power aroused the people, and like the jailer, they began to inquire, "What must I do to be saved?" But these shepherds stepped in between the truth and the people, and preached smooth things to lead them from the truth. They united with Satan and his angels, crying, "Peace, peace," when there was no peace. Those who loved their ease and were content with their distance from God would not be aroused from their carnal security. I saw that angels of God marked it all; the garments of those unconsecrated shepherds were covered with the blood of souls. {EW 233.2}

We are not to be engrossed with speculations in regard to the times and the seasons which God has not revealed. Jesus has told His disciples to "watch," but not for definite time. His followers are to be in the position of those who are listening for the orders of their Captain; they are to watch, wait, pray, and work, as they approach the time for the coming of the Lord; but no one will be able to predict just when that time will come; for "of that day and hour knoweth no man." You will not be able to say that He will come in one, two, or five years, neither are you to put off His coming by stating that it may not be for ten or twenty years. . . . We are not to know the definite time either for the outpouring of the Holy Spirit or for the coming of Christ.--Review and Herald, March 22, 1892. {Ev 221.1}

Many who have called themselves Adventists have been time-setters. Time after time has been set for Christ to come, but repeated failures have been the result. The definite time of our Lord's coming is declared to be beyond the ken of mortals. Even the angels, who minister unto those who shall be heirs of salvation, know not the day nor the hour. "But of that day and hour knoweth no man, no, not the angels of heaven, but My Father only."--4T 307 (1879). {LDE 32.3}
We are not to know the definite time either for the outpouring of the Holy Spirit or for the coming of Christ. . . . Why has not God given us this knowledge?--Because we would not make a right use of it if He did. A condition of things would result from this knowledge among our people that would greatly retard the work of God in preparing a people to stand in the great day that is to come. We are not to live upon time excitement. . . . {LDE 33.1}
You will not be able to say that He will come in one, two, or five years, neither are you to put off His coming by stating that it may not be for ten or twenty years.--RH March 22, 1892. {LDE 33.2}
We are nearing the great day of God. The signs are fulfilling. And yet we have no message to tell us of the day and hour of Christ's appearing. The Lord has wisely concealed this from us that we may always be in a state of expectancy and preparation for the second appearing of our Lord Jesus Christ in the clouds of heaven.--Letter 28, 1897. {LDE 33.3}
The exact time of the second coming of the Son of man is God's mystery.--DA 633 (1898). {LDE 33.4}

Ours Is Not a Time-setting Message

We are not of that class who define the exact period of time that shall elapse before the coming of Jesus the second time with power and great glory. Some have set a time, and when that has passed, their presumptuous spirits have not accepted rebuke, but they have set another and another time. But many successive failures have stamped them as false prophets.--FE 335 (1895). {LDE 34.1}
God gives no man a message that it will be five years or ten years or twenty years before this earth's history shall close. He would not give any living being an excuse for delaying the preparation for His appearing. He would have no one say, as did the unfaithful servant, "My lord delayeth his coming," for this leads to reckless neglect of the opportunities and privileges given to prepare us for that great day.--RH Nov. 27, 1900. {LDE 34.2}

Many who have called themselves Adventists have been time setters. Time after time has been set for Christ to come, but repeated failures have been the result. The definite time of our Lord's coming is declared to be beyond the ken of mortals. Even the angels who minister unto those who shall be heirs of salvation know not the day nor the hour. "But of that day and hour knoweth no man, no, not the angels of heaven, but My Father only." Because the times repeatedly set have passed, the world is in a more decided state of unbelief than before in regard to the near advent of Christ. They look upon the failures of the time setters with disgust; and because men have been so deceived, they turn from the truth substantiated by the word of God that the end of all things is at hand. {4T 307.1}
Those who so presumptuously preach definite time, in so doing gratify the adversary of souls; for they are advancing infidelity rather than Christianity. They produce Scripture and by false interpretation show a chain of argument which apparently proves their position. But their failures show that they are false prophets, that they do not rightly interpret the language of inspiration. The word of God is truth and verity, but men have perverted its meaning. These errors have brought the truth of God for these last days into disrepute. Adventists are derided by ministers of all denominations, yet God's servants must not hold their peace. The signs foretold in prophecy are fast fulfilling around us. This should arouse every true follower of Christ to zealous action. {4T 307.2}
Those who think they must preach definite time in order to make an impression upon the people do not work from the right standpoint. The feelings of the people may be stirred and their fears aroused, but they do not move from principle. An excitement is created; but when the time passes, as it has done repeatedly, those who moved out upon time fall back into coldness, darkness, and sin, and it is almost impossible to arouse their consciences without some great excitement. {4T 308.1}
In Noah's day the inhabitants of the old world laughed to scorn what they termed the superstitious fears and forebodings of the preacher of righteousness. He was denounced as a visionary character, a fanatic, an alarmist. "As it was in the days of Noah, so shall it be also in the days of the Son of man." Men will reject the solemn message of warning in our day, as they did in Noah's time. They will refer to those false teachers who have predicted the event and set the definite time, and will say that they have no more faith in our warning than in theirs. This is the attitude of the world today. Unbelief is widespread, and the preaching of Christ's coming is mocked at and derided. This makes it all the more essential that those who believe present truth should show their faith by their works. They should be sanctified through the truth which they profess to believe; for they are a savor of life unto life or of death unto death. {4T 308.2}
Noah preached to the people of his time that God would give them one hundred and twenty years in which to repent of their sins and find refuge in the ark, but they refused the gracious invitation. Abundant time was given them to turn from their sins, overcome their bad habits, and develop righteous characters. But inclination to sin, though weak at first with many, strengthened through repeated indulgence and hurried them on to irretrievable ruin. The merciful warning of God was rejected with sneers, with mockery and derision; and they were left in darkness to follow the course that their sinful hearts had chosen. But their unbelief did not hinder the predicted event. It came, and great was the wrath of God which was seen in the general ruin. {4T 308.3}

The world placed all time-proclamation on the same level and called it a delusion, fanaticism and heresy. Ever since 1844 I have borne my testimony that we were now in a period of time in which we are to take heed to ourselves lest our hearts be overcharged with surfeiting and drunkenness, and cares of this life, and so that day come upon us unawares. Our position has been one of waiting and watching, with no time-proclamation to intervene between the close of the prophetic periods in 1844 and the time of our Lord's coming. We do not know the day nor the hour, or when the definite time is, and yet the prophetic reckoning shows us that Christ is at the door. {10MR 270.1}

This was the document I came upon last Monday in searching over my writings, and here is another which was written in regard to a man who was setting time in 1884, and sending broadcast his arguments to prove his theories. The report of what he was doing was brought to me at the Jackson, Mich., camp-meeting, and I told the people they need not take heed to this man's theory; for the event he predicted would not take place. The times and the seasons God has put in his own power, and why has not God given us this knowledge?--Because we would not make a right use of it if he did. A condition of things would result from this knowledge among our people that would greatly retard the work of God in preparing a people to stand in the great day that is to come. We are not to live upon time excitement. We are not to be engrossed with speculations in regard to the times and the seasons which God has not revealed. Jesus has told his disciples to "watch," but not for definite time. His followers are to be in the position of those who are listening for the orders of their Captain: they are to watch, wait, pray, and work, as they approach the time for the coming of the Lord: but no one will be able to predict just when that time will come: for "of that day and hour knoweth no man." You will not be able to say that he will come in one, two, or five years, neither are you to put off his coming by stating that it may not be for ten or twenty years. {1888 959.3}

And I saw a flaming cloud come where Jesus stood and he laid off his priestly garment and put on his kingly robe, took his place on the cloud which carried him to the east where it first appeared to the saints on earth, a small black cloud, which was the sign of the Son of Man. {DS, March 14, 1846 par. 2}

Then I saw that after Jesus leaves the sanctuary the plagues will be poured out. Said the angel, It is the wrath of God and the Lamb that causes the destruction or death of the wicked. I saw that at the voice of God the saints will be mighty and terrible as an army with banners, but they will not then execute the judgment written. {12MR 248.2}

When Christ shall cease His work as mediator in man's behalf, then this time of trouble will begin. --PP 201 (1890). {LDE 253.1}

When Jesus leaves the most holy His restraining Spirit is withdrawn from rulers and people. --1T 204 (1859). {LDE 255.1}

I saw that the four angels would hold the four winds until Jesus' work was done in the sanctuary, and then will come the seven last plagues. --EW 36 (1851). {LDE 256.2}

When He leaves the sanctuary, darkness covers the inhabitants of the earth. In that fearful time the righteous must live in the sight of a holy God without an intercessor. --GC 613, 614 (1911). {LDE 265.6}

That's an interesting case, Mike, and one which I do have questions about. I had always believed it until I looked further into it once several years ago, at which point I came across a few uncertainties. Mrs. White herself makes little mention of this (the quote you found is the only one), and it appears that little was said about this after its date had passed. I am not saying here that I do not believe it, only that I do not find a strong case for it, and I'm open to reinterpreting it.

As for the trumpets themselves, I think events like 9/11 might have something to do with them. Again, I'm still trying to understand these things.

Our position has been one of waiting and watching, with no time-proclamation to intervene between the close of the prophetic periods in 1844.

You will not be able to say that He will come in one, two, or five years,

Great changes are soon to take place in our world, and the final movements will be rapid ones.--9T 11

Dedication, I believe the following passages make it clear Jesus will leave the sanctuary when probation closes. While en route to the east, which will take "a number days", the details described in GC 613-641 will unfold.

Do you really think Christ will already be on the cloud coming to earth throughout the whole of the endtime events? . . . To say Christ mounts the flaming cloud that carries Him to earth, at the beginning of the events in chapters 39-40 while she mentions it at the end, kind of throws the whole sequence of what she's saying out, unless it will be a very slowly approaching object.