I purchased a 6.1 receiver and the Polk RM satellite speakers not thinking that I needed one more speaker for rear center. I do have a Mission center speaker I think it may be a 70C1. I was pondering the idea of using the Mission for the front center and use the Polk speaker for the Center rear. Is this a good idea? I am afraid they will not match well. My other option is just to use a cheap cube speaker for the center rear.