Speedie, (1.) the general suggestion is to have the mains separated about as much as the distance of the listening position from them, so that 9'5" isn't bad. As far as going wider by being closer to a corner, if the centers of the woofer cones aren't at the same distance from the three nearest room surfaces(floor, side wall, front wall)it isn't harmful to be close to a corner. The purpose of having those distances different is so the reflections from the boundaries don't pile up at the same frequencies and cause a big peak and valley in the bass.
(2.)Good to hear that despite your doubts in your previous thread that you'll be able to use the QS8s. Since you're going to be very close to the back wall, the best location for the QS8 side surrounds is on the back wall about 2-3' above ear level and separated as widely as possible, almost to where they would be if on side walls.
