Thanks for the feedback on the soundstage depth question. It seems you are taking more of a studio/HT approach to your treatment situation. Be careful with thinking purely LE/DE. Seems like you are being pretty experimental and staging your process. No doubt you will get exactly what you want in the end.
Generally, a deep front to back soundstage is desired for 2ch setups. The speakers tend to "dissapear" more I find. I have also found that absorbtion directly behind the listening position pushed vocals back to the speaker plane from forward as well. This might help you if you prefer all elements on the speaker plane only.
I have found slatted blinds do a good job of breaking up glass reflections if curtains arent your thing. You can play with the tilt. A somewhat "variable" high frequency diffuser. Definitely better than glass in any case.
