FWIW, Audyssey (no "the" and a y in the middle there) doesn't select crossover settings. The receiver manufacturers, for whatever reason, insist on keeping that to themselves.
If the surrounds are the identical speakers, then you are an unusual case and without a sub, there's no reason to cross them over at all. I'd set them at "large" (something I can't ever remember recommending before) because they'll handle whatever lows are in the program just as well as the identical fronts, and may keep some load off the fronts if the surrounds happen to have a lot of lows. All IMO, YMMV, Please Don't Shoot the Piano Player, etc.