Yall are talking about the FX-1/08+ SJ Destroyers? I know the others aren't an exact fit, but I thought Blowsion would be good about that with as good as the others fit SJ's.
I have only had Tom21's on my 550, but his products are always a great fit and great quality. The only other advice I'd give is if you want to race, go for Tubbie 1 or 2's as they are legal and will bend easier than destroyers to fit the hull. I'm debating what tubbies I want right now as well.