i always leave snare and kick centered. i play only two toms and pan them equally left and right based on how i see them from the throne. Overheads are the same thing, i use two OH's and pan to either side. i find that the farther apart i pan the different parts the worse the kit sounds as a whole, but maybe thats just me. just try anything and everything and listen to all the differences. drum mixes are very important to the overall track but youll find something for sure.