For the issue of having only one hole, if the alternative is to toss the foot anyway, one might as well drill another hole in the one you have.
I made a custom plate for mine, with shallow milling on the top to match the shape of the original foot so it won't turn, but also drilled an extra hole and put in a pointed setscrew. It's quite stable now on a side-mounting gimbal. If you are using a ready-made plate which doesn't provide a good place for a hole, you can remove the foot, drill and tap a hole from the top down, and put in either a pointed setscrew or a plain bolt. If you drill a shallow recess in the plate where the bolt hits it, you won't have to make any of the attachments gorilla tight to keep it from ever turning.
The foot itself seems pretty sturdy, and I suspect any added flex will be in the tripod and head first. By the way, the extra 1/4 inch holes in the plate shown are for screwing it into a monopod, approximate balance points at 200 and 500.