Thanks for the advice Ethan. As additional info, I have superchunk traps at front two corners floor to ceiling, and a nice stretch of 703 in a recess in the ceiling behind the screen/soffit, as well as front wall treated with Linacoustic (behind screen wall). I also put about 6 4"x14" riser vents along back and side walls.
So far, I have not detected excessive bass build up anywhere in the room at using a single SVS sub. What I am noticing though is that I think the room is too "alive" with the higher frequencies, although I don't know what a really good audio response across the room should be due to inexperience. Just feels like the high end needs tamed down.
I will have to think more about going with 2" vs. 1" thick panels all around, and maybe consider if I can fit a smaller version of the superchunk construction in the back two corners (it's pretty tight there).
If you have any change in suggestions based on this additional info, please let me know.