I picked up a pack of extra large brass grommets at Holly Lobby.
I didn't try them though compressed closed cell foam yet , so I don't know if they would work through much more than heavy fabric .
You might try a leather supply company like tandy..and one more that I can't remember right now.
The strength of the base material would make the difference as would any plastic stiffener.

More than likely, you would need to use a hole punch through a piece of nylon webbing. Heat the raw edges. Heavy duty grommet.
Sew that with bar tac box stitch onto the belt. There are other designs that would work, but this method is simple and easy.
It only involves one extra step.

Tex 70 Nylon is the best thread by far if you plan to sew different bags to make the frame modular. It's only available on line, but is well worth the extra little cost and effort.

Last edited by Happy_Camper; 07/25/21.