can someone help me with figuring out these few chords?

axisus · May 2016

I've been trying to transcribe this old prog track, with the idea of recording a version playing all instruments. A big task for me as I'm bad at transcribing and learning stuff. Anyway, I've fought through 6 mins of guitar widdle, but I'm a bit stuck on the last phrase. The problem is that it will be powerchords rather than widdle and I can't seem to get a grip on chords. This section is only a few seconds long and gets repeated 3 times, I would be most grateful if someone could come up with the right chords to play under this 13 second keyboard finale.