I had the same issue with the Best straps. Too big for my feet. I tried the inner tube deal and honestly hated it.
I switched to Dakine x-lace straps which work super well for smaller feet, and not so well for bigger feet (I'm told). The bonus is when I have to wear booties, I can make them a little bigger and cinch them in on the fly.
dakine are great for that kind of thing, i remember reading a post sayingabout boards and sq replyed that brands who specialise in one thing produce a great area of products hence best with awsome kites but not rated boards if u know what i mean? (not takin a stab im just quoting). and dakine consentrate JUST on accesories so to make there money they have to make the best of the best accesories to compete, ill never buy harnesses from anywhere else i think (dont hold me to that troy) there just so nice n comfatabl, thay are the only harness ive owned but i have tried many others includeing maui magic's but i agree that u wud have a safe bet puting another brands straps on it and it feeling 10xbetter, u get me?