If I were you, I would present this picture in a new thread at Gearslutz in the Studio Building/Acoustics forum. There are many way qualified people who will answer your question much better than I. I am not sure what is best with your extruding areas. They will have better advice.
From what I have learned, You want at very least, 4" from floor to ceiling in the corners. Superchunk type would be even better. Your first reflection points, including a panel above (cloud), could probably be just 2", but considering the small space you have, the best would probably be to straddle all or the wall to ceiling corners with 4" panels as well. Again, get advice from the pro's. I have just learned from them.