I've read the 3 cross is supposed to be more durable (more crosses, the better up to a certain point). 32 up front should be plenty.
As far as the rear, some say 36 is stronger. I had a bud that had a 36 rear CXP fail on him. Might have been the builder's fault, maybe. Good builder is a big part of the durabilty factor. If you know you will drop weight, go 32. If you think it will be a problem keeping weight off later, go 36.
Don't go for the "I'll buy a smaller wedding dress size" cause I'll lose weight for the wedding.

......Good thing I talked Gina out of it or we'd still be waiting to get married!
You should be good either way, 32 or 36 in the rear! 36 should be stronger in theory.