I think QSx'ss all round are recommended unless you have enough distance behind the seating area that room reflections will have a chance to diffuse the sound from the rear speakers.

I have something like 9 feet between seating and rear speakers which should be enough for direct (M2) speakers to work well. If I ever get my 7.1 receiver back from repair I'll be able to report on how it works ;\)

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8