Another factor of toe overlap has to do with the type of cages, too.
I run Large plastic wellgo pedals with nylon straps, and I can just barely touch the wheel with my feet if my wheels are turning more than 45 degrees... which realistically doesn't happen unless I'm stopped.

Make sure that your feet (with largest type of shoes you'll be commonly riding with. Like runners) don't touch the wheel when cornering or turning at a reasonable speed. This made me go from 175mm to 165mm and right now i'm golden.