Welcome to the Axiom forum MNCold,
I changed the title of the thread to QS8 location. The QS8's can work in a lot of different loctions. Typically you want to place your surrounds to the side, however it shouldn't be a problem placing them on the back wall behind the couch. Are you saying you plan on placing them 5-6 above the seating position or 5-6 feet apart?
10 - 11 feet apart is not too wide and with a viewing distance of 13 feet approximately the VP150 should have no problem filling that space. As Adrian noted, I would also try toeing the M60's toward the couch or "sweet spot".
Good luck
