Thanks that helps. I do have a opening to the rear and right of listening position that is about 1800cf.
I am officially without subs as of this afternoon. I had 2 HSU MBMs and a VTF3-MK3 Turbo. In the end I was running with just the 33T which I liked best without MBMs.
I want just one sub that does as good with music as the 33T and have 6db more SPL for movies.
I have sent my room drawing to SVS and Epik sales. I like what I read about the Ultra and SVS. SVS customers seem to like their customer service which is something I really liked about HSU.