Fact : Black Bears are best
Another fact : inwall is worst possible way configuration especially for front speakers.
Fact 3) I'm not sure how much you have paid for your Polk speakers, but I do know that you got pretty bad value for it
As for your specific question : Polk specifically recommends (quite sensibly btw) to have identical rc85i for left, centrer and right front speakers and smaller rc65i for surround duty.
Hope you didn't buy Polk subwoofer