I was looking for an easy way to set my toggle clamps when I saw this at Rockler : https://www.rockler.com/quickset-pressure-adapters.

Since I already had some clamps from Harbor Freight and Amazon (https://www.amazon.com/gp/product/B01N1UNOOM/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1), I made my own design to adapt to these clamps.

Side 1/4" thumb screw is 1/2" long, and is used to set the position of the hold down screw.
5/16" hold down screw uses a wing nut on top.

1/4" and 5/16" nuts are snapped snuggly in the printed part.

You can adapt the opening of the clamp if you have other dimensions.
Those fit perfectly with just enough play in the ones I have !