These folks offer a mating pair of 16mm neodymium magnets with a
center hole, which looks like it could be mounted with a rivet.
Let us know if you try it. I’ve been considering this with a bezel
surround (esthetic). Not sure about the strength of 16mm x 5mm
magnet, even though they are neodymium. There’s more and more demand
for magnet clasps with aging baby boomers’ arthritic fingers. One of
the finding suppliers (can’t remember which one) has a gold plated
magnet, but it doesn’t have a hole, and I don’t know if I’m ready to
trust a glued clasp.