For some reason I don't really like the left QS8 so close to the corner. It seems in your setup will be hard to get good left/right dispertion in the room from the surrounds.
I was looking at your pic, and I think it would make a lot more sense to move your TV to the other wall, the top wall on the picture.
That way, the QS8's can be nice and spread out to the side. You can put the one at the very end of the right wall. I think that would make a lot more sense.
If the couch would actually be behind the QS8's, you could mount the QS8's on the ceiling like sirquack has done. That would work really well too. Just depends where you want to be sitting.
I'd say if you had your couch 7 feet back, having the QS8's 10 feet back from the front wall (The farthest back you could mount on the wall because the right wall is a partial wall) that would be perfect, with the QS8's mostly to the side and a tiny bit behind. If you move your couch further back, do ceiling mounting.
Also, you would have a lot more options to move your sub around for the best sound.
