Okay Ryan, in your setup the QSs would work well on the back wall but they wouldn't be "directly behind" you. Yes, mount them flat up against the wall and separated as much as possible, to within maybe 6" of that right sidewall, and a similar distance on the left so that they'll be more left/right side surrounds rather than being in back. It's generally suggested that they be about 3' above ear-level, which might make their tops about even with the tops of the picture frames. The sub location wouldn't depend on the QS locations and the right front corner behind the TV might be a logical spot to try first, sliding it out a little to the left if the corner was too boomy.
