Ok Big, I pulled the 1/2 riser off the wall, Ran all my electrical, speaker wire, and got a quote for a general contractor to sheetrock the room. I've got a double wall on one side (3/4 plywood, 1/2 fibrous sound board, another insulated wall, then will be sheetrocked) a subwall to recess the screen in the front, and will either do the soundboard and sheetrock, or double sheetrock with green glue on the other wall.
Just ordered swatches for fabric, and will order my screen some time next month.
Going to build all "sound" panels for aesthetics, but will alternate 20% absorption/ 20% diffusion/ blank panels, concentrating absorption at the first order reflection points.
Thanks for all your advice, it's a bit overwhelming to put it all together into a plan. wish there was a reputable installer around here.
Tested the PJ at the proposed location at night with just a 40w bulb on, 16:9 and 168" diag. It showed a good image with bright turned off, and @65% brightness level of the projector. Pics Included