Well there yah go. Glad I asked! The material MATTERS. A lot.
Steel or hard bronze is one thing. Shiney wood or softer brass is another.
“Resilient” materials yah have to apply some SENSE, as the toe-clamp can destroy material, “locally”, as-in where it digs-in, still NOT hold it well atall, or even buckle or bow the material and pop it out, “tiddlywink” style.
You’ll probably want a ground tool-steel pressure-transfer shoe. Sorta like a vise jaw with a pair of toe-clamps providing the clamping force to be transferred at lower “point” pressure across a wider bearing area?
Not sure I’d be wanting to edge-clamp HDPE even so.
Some other Pilgrim who does it all-day, every day, will surely have better solutions.
You seek their expertise, shared, right helpful if you ALSO shared the dimensions and general shape of the blank you are trying to clamp, too.