Thanks for the suggestions Duffy. I've always shied away from the ladder type adjustment with the slots cut because anytime I ever used one it was all bunched up in back and changing the length was a pain. I make the straps to the length needed by the customer so having one adjust from 40" to 60" like commercial straps isn't really necessary. From talking with people most players never adjust the length of their straps after they set it to their preferred length when they get it. The Cut to Size style I make has been pretty popular with guys that don't need or want a buckle adjustment. I will often place 2 holes at the back spaced 2" apart that allow for some adjustment to compensate for the difference of summer to winter weight clothing.
But I'm always open to new buckle designs when I can find nice ones. A long time ago I made some cast brass buckles myself. Making the wax form, casting it in investment, baking the mold in a kiln to burn out the wax, and then pouring the brass and dressing up the casting was fun, but a real project.