What about a 36 rear and a 32 (or 36 front)? Wouldn't more spokes help also?
I agree. I'm close to that weight (240-ish) and I ride a recumbent so I can't "unweight" to protect the wheel. I've used 36-spoke rear wheels forever. I usually build them with 2.0/1.8/2.0 double-butted spokes and tension them high and even. They rarely need retruing. I've worn through 2 or 3 sets of rims thanks to our rain and rim brakes.
My latest bike has disk brakes. I built the wheels with H+ Son Archetype rims, 32 front, 36 rear. Thanks to the disks I hope they last forever.