Don't make no difference no how.
I've done it one time, Late July. Flow started out at 3500 cfs, dropped about 100 cfs per day. We had a 16' and a 14'. The bigger boat offers greater displacement which equates to great load carrying ability for the same draft. One had no advantage over the other. Btw, I used to own 5 boats, from 12-16 ft, a bucket, a cat, and the rest selfbailers. Now I'm down to one, and it's a 15 1/2 footer. If I could change anything, I'd get back the missing 6 inches. My wife asks for the same.