www.wholehyper.com has a little info on the "grading" system. But there are some really bad CF hoods out there. Some that are so thin that you could see right through them.

If you are shopping for a CF hood and you don't trust the grading system, I'd suggest that you get a look of the hood yourself. Some of the key areas where a CF hood is good, is rolled edges, a really strong latch and a good gelcoat/clearcoat on it.