Looking for a little help here. I currently have a 7.2 setup (front heights). My current side surrounds are a bi-polar speaker.

I'm looking at ordering a pair of the QS10, as the quad-polar setup intrigues me. Assuming that I use them on the side (replacing the bi-poles), how high should I mount them? I believe the current bi-poles (middle of the drivers) are about 1 ft above my seated (at MLP) head height.

Also, I have long been considering adding speakers on the back wall (pre-wired) for a 9.2. Back wall is only 2 - 3 ft behind MLP, and there is an opening to a stairwell on one side. Would a 2nd set of QS10's on the back wall make sense? Or use QS10's on the back wall and something like an M3 on-wall on the sides instead? (Note, I doubt I will ever get the chance to go Atmos as drilling holes in my ceiling is not really in the cards)

I'm trying to sell my current speakers so that I can go with 100's in the front, with a 160 or 180 centre. Don't know what I would use for front heights. Thought about an M3 on-wall with the full metal bracket mounting so that I could swivel/tilt them toward MLP.