Thanks for the advice, my room is 22X18 with a 10 foot ceiling that slopes up to 19 feet. The main listening area is on the back wall so the rear speakers are on the wall 12 inches from my head.
Also when I add the side surrounds, the left side surround will be 2-3 feet higher in elevation than the right side surround speaker. Will this affect the listening experience much? All my others speakers are equal ratios.