I listen at approx 9' in a room that measures 50' wide x 20' deep x 13' high....pretty big. The speakers are located 4' from the back wall and about 20' from the side walls, I listen from almost smack dab center of the room.
I'm curious to know how you feel about the use of a matched stereo pair of amplifiers vs. a pair of mono amps aside from the fact that I will realize more power with mono's. With the matched stereo pair I could vertical biamp, one channel to the bass section and one channel to the mtm portion of each speaker thus eliminating any clipping artifacts from disturbing the entire set of drivers. I currently vert biamp with my SP Tech Timepiece 2.1's which have a sensitivity of 85db/1w/1m because of clipping related issues with the loaded tweeter.