Welcome!
That would be a WONDERFUL system.
Well, your wife has picked what appears to be the best spot for the front sound stage, bless her. I think the 11 foot wall will be long enough to handle your display, speakers and equipment (I'll refer to this wall as the "front wall").
Not sure where the best place for your sub would be, but with an EP600, it may not matter. That sub will rock the house. Experiment with placement until you find the best spot for it that your wife can live with.
I'm assuming that the seating, be it chairs or sofa, will be away from the wall since there appears to be a door in the wall opposite the front sound stage ( I will refer to this was as the "back wall"). Allowing 3 feet for display, speakers and equipment, and, at least, 3 feet behind the seating for the door to open, that will put you anywhere from 8 to 10 feet from the speakers and display. Close, but not too close. I sit about 8 feet from mine.
Your biggest problem will be placement of the QS8s. Since you have the seating away from the back wall (assuming that's correct) placing them on the back wall itself, one on either side of that door, at points equidistant from the sweet spot in the listening area, might work.
The only alternative I see, would be putting them on the side walls, one QS8 just to the side of the door in the 6' wall (the side closest to the front wall, assuming there's room for it there), the other on the wall with what appears to be a fireplace next to double doors. This would leave them at different distances from the listening area, but the QS8s are very forgiving when it comes to placement. That, and the ability to adjust for distance in your receiver's speaker setup menu, might allow for such placement.
Again, experimentation with positioning is the key here. Placing the QS8s on stands would be the only other thing I could think of.
Hopefully, others will chime in with more suggestions.
