Can't comment on the Williams, but I rode RS10 16f/20r (OEM wheels on my Synapse) for about a thousand miles or so at weights from 200-210 without any issues at all, though I would never discourage anyone from trying something else. In fact, just for fun I bought a pair of Neuvation's cheapest wheels (M28X Aero, again 16f/20r) and they worked great for me, too. Now that I've put a few (!) pounds back on, I built myself a pair of 32-spoke HED Belgiums for their wider (22m) profile, and love them.