Are you saying your vet implied skin and coat problems for large dogs from spaying? I've never heard anything like that, but also never owned a large dog. Every dog my family has ever owned has been spayed before ever going in heat without problems.

You should prevent jumping after the surgery but recovery isn't all that long. Sadie took a big jump off of a porch the day I brought her home from her spaying but she only let out a yelp and kept going. It's hard to tell a young dog she should take it easy til she heals!