IME, the amount of room treatment required depends more on the room than the speakers. Of course, dipole speakers require different combination of treatments than monopole speakers. At this point, the soundstaging and imaging are life-like...huge when required and intimate when called for. The tonal balance is nearly perfect to my ears. Haven't yet confirmed it with sound pressure meter. I found out the sibilance on vocals were caused by slap echo/flutter in the room, not my electronics, wires, or speakers. The diffusion pretty much got rid that problem.
Yes, I saw your room. Seems like a difficult room given the irregular room shape, but sometimes that works to one's benefit.
Are you going by Roberts recommendation on speaker placement, literally 2/3 into the room with listening seat nearly against the back wall? This can give very good sound stage, but I've encountered too much problems in other areas...bass boom, flutter/echo and sibilance especially on vocals.
