Basic opinons on some things that have been talked about:

I also got the impression that Kingsridge is more higher learning than high school. I wrote my character under the assumption that he's already a fully qualified wizard, and is merely continuing his education. I would reckon it's a lot more like college than high schools. Which makes me wonder if there's a uniform? I thought probably not. 

Hogwarts itself actually didn't have anything like core classes after fifth year. After taking the OWLs everyone was free to drop or continue any classes they wanted. Neville Longbottom, for instance, actually couldn't continue a class(I think Potions off the top of my head) past fifth year because of his test scores. Do we have OWLs and NEWTs in America?