Jack, valid point thanks. A little further explanation is in order. My home is a 4-level split home and the black lines labled "wall" are actually the 2x4 framing that support stairs going to the upper level. So in the diagram you have a set of stairs that go from the basement level, where the HT is being built, up one level (the stairs labled in the diagram), then they wrap around and go up to the next level (the black lines labled wall support these steps).

The wall the Screen is on will be finished. The side of the stairs next to the left front speaker will only be finished on the stairwell side with insulation between studs. I'm hoping this will help reduce, probably not eliminate, any reflections from the LF speaker.

The center channel will be next to the other stair support and left unfinished, therefore there shouldn't be any reflections of consequence.

I know I'm bending the recommendations of Alan and others about the effects of placing the speakers in cabinets, but it is the best comprimise I could think of (WAF factor). Any other suggestions would be welcome, besides getting rid of the wife .