When I make contemporary kilts for my friends, I use side release buckles, and webbing as the closures. When I buy the more expensive brand at our local fabric store, I can do them one handed, when I'm cheap, they take two hands and prayer. A hint from experience, before adding the side release buckles, I pin the kilt on the person and mark where they need to line up, because doing it off the person makes me miss the location badly. I've never messed up actual buckles, so I don't know what my mental block is.

Good luck on this interesting construction problem!
Chris