I am setting up a 19x12 room and want to use 4 FXi3 speakers in a 7.1 setup for both the surround and back speakers. The speakers will be mounted on the side and back walls. The surround speakers are going to be 6’10” high and 3’4” from the back wall. The rear speakers are going to be 6’7” high and 4”7” from the sidewalls, leaving 10” between the rear speakers. I have a door and window on the back wall so I cannot mount them further apart, I have about 7” above the door and window. Do you think this setup will work ok? Suggestions please.