I would be thrilled just to have the space for 3 towers for my LCR. But your question was if you could so...yes, if I had the room and finances I would use all towers. Well, 9 towers, I can't imagine trying to hang 2 towers near the ceiling angled down for front heights. :-)

UMC-200, XPA-3, XPA-5, iNuke 3000DSP, M22's for LCR, 4 QS8's, 2 Ultimax 15" in DIY 12cuft ported box