Your study on the 7 trumpets does not line up at all with the pioneer understanding and teaching or the teaching of Ellen White. See the Great Controversy 334-335. I have inserted it here. You will note that the prophecy that Ellen White says is fulfilled in 1840 is Revelation 9:15, the 6th trumpet.

In the year 1840 another remarkable fulfillment of prophecy excited widespread interest. Two years before, Josiah Litch, one of the leading ministers preaching the second advent, published an exposition of Revelation 9, predicting the fall of the Ottoman Empire. According to his calculations, this power was to be overthrown "in A.D. 1840, sometime in the month of August;" and only a few days previous to its accomplishment he wrote: "Allowing the first period, 150 years, to have been exactly fulfilled before Deacozes ascended the throne by permission of the Turks, and that the 391 years, fifteen days, commenced at the close of the first period, it will end on the 11th of August, 1840, when the Ottoman power in Constantinople may be expected to be broken. And this, I believe, will be found to be the case."--Josiah Litch, in Signs of the Times, and Expositor of Prophecy, Aug. 1, 1840. {GC 334.4}
At the very time specified, Turkey, through her ambassadors, accepted the protection of the allied powers of Europe, and thus placed herself under the control of Christian nations. The event exactly fulfilled the prediction. (See Appendix.) {GC 335.1}

Here is the Appendix comment: FOR THE LATTER CHAPTER, UNDER THE "HOUR, DAY, MONTH, YEAR" PROPHECY, AS PART OF THE SIXTH TRUMPET, JOSIAH LITCH WORKED OUT AN APPLICATION OF THE TIME PROPHECY, TERMINATING TURKISH INDEPENDENCE IN AUGUST, 1840. LITCH'S VIEW CAN BE FOUND IN FULL IN HIS THE PROBABILITY OF THE SECOND COMING OF CHRIST ABOUT A.D. 1843 (PUBLISHED IN JUNE, 1838); AN ADDRESS TO THE CLERGY (PUBLISHED IN THE SPRING OF 1840; A SECOND EDITION, WITH HISTORICAL DATA IN SUPPORT OF THE ACCURACY OF FORMER CALCULATIONS OF THE PROPHETIC PERIOD EXTENDING TO THE FALL OF THE OTTOMAN EMPIRE, WAS PUBLISHED IN 1841); AND AN ARTICLE IN SIGNS OF THE TIMES AND EXPOSITOR OF PROPHECY, AUG. 1, 1840. SEE ALSO ARTICLE IN SIGNS OF THE TIMES AND EXPOSITOR OF PROPHECY, FEB. 1, 1841; AND J. N. LOUGHBOROUGH, THE GREAT ADVENT MOVEMENT (1905 ED.), PP. 129-132. THE BOOK BY URIAH SMITH, THOUGHTS ON DANIEL AND THE REVELATION, REV. ED. OF 1944, DISCUSSES THE PROPHETIC TIMING OF THIS PROPHECY ON PAGES 506-517. {GC 691.2}

Get as copy of Daniel & the Revelation by Uriah Smith to get a correct understanding of the trumpets. Sister White calls that book "God's helping hand":

This book has been the means of bringing many precious souls to a knowledge of the truth. Everything that can be done should be done to circulate Thoughts on Daniel and the Revelation. I know of no other book that can take the place of this one. It is God's helping hand. {21MR 444.3}

God Bless you as He guides you into all Truth.

I can't date Revelation 8.2 but I can date Revelation 8.1 and it is from 8th Ferbrary 1990 to 16th December 2010. It is "about half an hour" out by 7 days and accurate to 99.9808% or thereby.

The 7th Trumpet is the Second Coming.

The other 6 are:

1. Hail - and fire mixed with blood cast upon the earth = Aerial warfare so WW1 WW2 etc.

2. Something like a mountain on fire cast upon the sea = The atomic bomb.

3. It made the waters bitter and men died drinking the bitter waters. Its name is Wormwood. Wormwood in Ukranian is Chernobyl.

4. 1/3 sun, moon and stars loose their brightness = Chemtrails.

5. Out of the smoke came locusts with the faces of men with a tail like a scorpion... One ruled over them called "the destroyer": Kuwait War, burning oil fields, attack helicopters. Saddam means "the destroyer".

6. Euphrates. 200million troops 1/3 mankind destroyed. This is WW3 starting in Iraq and clearly involving China. It has begun.

And by the way the fire from the alter cast upon the earth is Love = 1 Cor.13, long suffering and it's record is the Little Scroll of Revelation 10 being sweet in the mouth and sour in the stomach.

We also know exactly where the earthquake of Revelation 8.5 will be, it being the fulfillment of Malachi 3.5 brought about principally by "the adulterers" who violated the Covenant of Love.

Hope to produce soon:

The Book of Love.

The Lord is God.