Randy I planned the layout for all of the speakers in our room using Alan's setup guide for 'Dolby Digital EX/Dolby Pro LogicIIx/7.1 channels' in his
"Essential Guide to Home Theater Layout" article. I used a common protractor then marked the suggested speaker locations in degrees on a garage workbench stool with a magic marker, placed the stool in the primary listening position (sweetspot) with the center aimed directly to the center of the main wall and then used a laser light pen and a pencil to mark the location on each wall for each speaker.
As to mounting the QS8s, I initially was going to use some recessed wall plates from PartExpress but chucked that idea whenever I found how much of a PIA it was going to be trying to connect a short run of wire between the plate and the QS8 and instead went with a bare wire sticking out of the wall, much easier and simpler. Without seeing exactly what your you are dealing with on the wall without a void, I really don't know what to suggest there.
Dolby Digital EX/Dolby Pro LogicIIx/7.1 channels 
