I have been dropping Gees minnow traps in small creeks around me but most of the chubs inside are pretty small. Would I be more likely to find some chunkers closer to the bigger rivers?

I always had better luck catching larger chubs and shiners with a tiny hook and a bit of worm. It really weeds out the smaller ones. Also, any good current break with some depth should have them. But to answer the original question, yes.