Add one more to the M80 scenario.
I also agree with Randy's (Sirquack) advice. I will add that I find in a large room or if you are at least able to get some breathing space between that last row of seats and the rear channels you can use direct radiating speakers as there will be enough room to allow natural dispersion to work, the closer back to the rear channels you move the better a multi-firing speaker, like the QS series will work. What you don't necessarily want is for the rear channel to be mounted right above you, as the sounds are meant to be coming from behind you, but I think this could be more of a personal preference.
