Thanks y'all. Sounds like I'll probably want to stick with the 30s and just try not to get fat(ter).
The cotton jaspe Clydes from this season have bracers buttons rather than a buckle back. Also, I haven't tried it myself, but I think some people have removed the buckle backs from their trousers (or had a tailor do so).
I have a pair of olive herringbone chinos (they called them "Marine Corps olive") that have riveted metal buttons that I'm pretty sure are officer chinos. No buckle back or anything on those.
I have removed the buckleback from two pair of clydes. Very easy to do with a seam ripper.