If you look at the apocalypse(John's revelation) as a wheel, the seals are the rim, the various visions and declarations and prophecies are the spokes, and the revelation of Jesus at the "ephiphana" or "parousia" of Messiah is the hub.
In such a view, the trumpets and the bowls occur simultaneously, alternating towards the conclusion of the visions...... notice:
second trumpet- 1/3 sea becomes blood
second bowl- all the sea becomes blood
third trumpet- 1/3 rivers and springs become blood
third bowl- all the rivers and springs become blood
fourth trumpet -1/3 sun darkened
fourth bowl- sun scorches men with intense heat
fifth trumpet- poured on the throne of the beast they gnaw their tongues for pain
fifth bowl- Abbadon opened locusts as scorpions descend upon all who do not have the seal of God in their forheads
sixth trumpet- four angels bound at the river Euphrates released, 1/3 mankind killed by war
sixth bowl- poured out on the river Euphrates to dry it up and make it a thoroughfare for the kings of the east
seventh trumpet- in the days when the seventh trumpet is sounded the mystery of God is finished..."The kingdoms of this world have become the kingdoms of our God and His Messiah and He will rule unto the age of the ages
seventh bowl- "It is finished"
And I saw another sign in the heaven, great and wonderful, seven messengers having the seven last(eshcatos) plagues, because in these was completed(teleo-filled up discharged) the wrath of God, (Rev 15:1) This being properly translated (IMO) would indicate that the bowls are the "completing" judgments- like in a one two punch, one being the trumpet, two being the bowl.
I believe the two witnesses are calling down these plagues, trumpet (1/3) then bowl (filled up), trumpet, bowl, etc.
The timeline of the narration(regardless of whether one considers this to be literal, typological, or both) is that from the opening of the sixth seal on to the seventh all visions(the trumpets, the bowls, the two witnesses, the giant messenger, etc.) are spokes in a wheel. The parousia/ephipania of Messaih is the hub- notice:
Seventh trumpet- "the mystery of God is finished" (Behold I show you a mystery we shall not all sleep but we shal all be changed in a moment, in a twinkling of an eye, at the last trumpet" "for the trumpet shall sound and the archangel shout")- "the kingdoms of this world are become the kingdoms of our God and His Messiah"
Seventh Bowl- "It Is Finished", every mountain leveled every island flees away, Babylon judged
These have the power to shut up the sky, so that rain will not fall during the days of their prophesying; and they have power over the waters to turn them into blood, and to strike the earth with every plague, as often as they desire. (Rev 11:6)
And those who dwell on the earth will rejoice over them and celebrate; and they will send gifts to one another, because these two prophets tormented those who dwell on the earth.
And they heard a loud voice from heaven saying to them, "Come up here"(first ressurection, in the cloud of overcomers, archangels shout, last trumpet, meet the Lord in the air) Then they went up into heaven in the cloud, and their enemies watched them.
Notice, immediately after the completion of the two witnesses course, the second woe(sixth trumpet) is past and the third(seventh trumpet) woe "comes quickly".
Rev 11:14 The second woe is past; and, behold, the third woe cometh quickly.
Rev 11:15 And the seventh angel (third woe)sounded; and there were great voices in heaven, saying, The kingdoms of this world are become the kingdoms of our Lord, and of his Christ; and he shall reign for ever and ever.
When Daniels sealed book is unsealed by the Lamb for John, we see as the seals are released, various visions of the unfolding completion of the plan for this age and glimpses in to both the "anakepholaomai" (Eph 1:10)...the "gathering into one" of all things; and the" apocastasis" (Acts 3:19) ...the restitution of all things (Rev 5:13 Rev 21:5,6). I personally believe the apocalypse that Jesus gave to John is both literal -towards the foreknown history of the end of the times(chronos) and seasons(kairos) of this age(aion)- and typological, revealing eternal truths always active in the NOW of the I AM-even as Daniels former revelation was also both literal and eternal(time transcending Now/I AM truth).
When the "Mystery of God is finished" as it speaks concerning the seventh trumpet- the lid will have been taken off, the veil torn so to speak, for all the world, concerning the purpose of the sons of God, which is the reconciliation of all things(Romans 8:19-30), which will be completed in the ages to come(Eph 2:7)-but not as a mystery. It will be completed as the open declared administration of God (Eph 1:9,10). Paul refers to this mystery in his epistles, especially Ephesians and Colossians. (Eph 1:9,10; 3:3,4,9; 6:19 & Colossians 1:16-27 & Romans 11:32-36; 16:25,56). When the parousia/epiphania/apocalupto/musterion of Christ is fulfilled at the end of this age(in the DAY/NOW/I AM of God it is already finished....and we are seeing it in the eye of faith, upon whom the ends of the age have come in Christ), the veil over heavens will be rolled away(all men will see the purpose of God), the sign of the son of man will appear in the heavens(all men will see the Lordship/throne of Yashua Moschaich).