I am in the process of applying for 501st entry. I just finished my armor and am very pleased with it. I am 180lb, 5'10", 36 waist. I went with ATA, and it fits great. It was not a simple build, as I've never done anything like this before. I just took my time, did a lot of research, and went with what I felt worked best for me. I did not need to shim the kit for my waist. It barley makes it lol. I did use elastic straps on the clam to allow some breathing room when needed. I was at first more concerned with height of the back.
To explain, the butt plate, kidney plate, and back plate should have no black gaps inbetween them. For the butt and kidney, that was simple. They are strapped together and start from the bottom and work up your backside. The back plate was the issue if it was to rest on the shoulders correctly and hang down. This is where height and body type can come into play, for if your back is too long, then you'll have some gap issues to address.
My vote is if you can fit in an ATA kit, then you should do it. I think the kit looks great
