There are a few folks around here that are sincere proponents of stereo subs, so what you are doing has been done in one form or another by several people. There's a thread or two somewhere around here with some good tutorials on stereo subs that might be of interest. If you have trouble getting three subs settled into your space, you could also consider stereo subs that share LFE duty. It may be a bit odd to do in light of the 950's triple crossover (and may introduce some concerns with channel delays, although I'm not sure), but you could think about setting all of your channels to "large" in the 950 and putting an ICBM between the 950 and the 7100. That would let the sub's LFE output and the crossed-over data from center and surrounds be split between two subs, each of which would be assigned the task of handling low frequency duties for their respective main speaker. It's a thought, and there are some other good ideas floating around the forum. As sluggo says, if you don't mind tweaking your system, the reports I've read indicate that it can yield some very positive results.