every room is different Bryan, you will need to experiment. I found that if I have my M80's pointing about 2ft behind my head it sounds great. My M80's are about 11-12ft apart and I tried many variations before settling on this.
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M80s-VP180-4xM22ow-4xM3ic-EP600-2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB SonyUBPX800