My receiver is capable of crossing over at 100, 150 or 200. My Sub is capable between 60 - 125. My question is what would be the optimal set up with the two? Should I have the sub at 125 and adjust with my receiver ( i'd assume to 100) or have the receiver at 200 and adjust the sub accordingly. Additionally my receiver can be set up as small or large speakers for all (front rear center) or any combination there of. I know it's what sounds best to me but what would you all reccommend? All small with the sub at 125 and adjust the xover with the receiver?

My set up is:
Pioneer 711 receiver
Polk R50 - front
Polk CSi30 - center
Polk R15 - surround
Polk PSW450 - Sub