I drew up some quick replacement jaws for small ratcheting clamps.

These have a 90° groove and teeth on one side for easily clamping round items.

The other jaw has is angled to account for flex in the clamps. This helps the jaws to clamp parallel.

Sorry these aren't parametric, it was just a quick Rhino sketch.

Print, slide into place.

If they're loose, a dab of glue helps to keep them in place.