In my normal room set up, I have my QS8's just a little past 90 degrees so their a little behind me and they sound good. In this picture the couch is off the wall by 2.5' to 3'
I recently moved my couch up a foot or so and the difference is really surprising. The QS8's sound so much better and lively now. I even went through rebalancing my system again to ensure they were not too "hot". So definitely try placements before attaching to the walls, but I believe due to your layout behind you will be better. Also, due to my OCD, I think having them both wall mounted on the back wall will make the room more balance and symmetrical.
