Hi Curl,
I was in touch with Mike within an hour of receiving your email directing me to this thread! Just fantastic looking work (and not only the swivels). Mike will of course speak for himself, but it sounds like the swivels are done in batches over the year and are not something that he has inventoried. I'm in for a set and we're discussing other reloading bits.

Re the noise issue-I wonder if wrapping the apex of the snap with a few turns of electrical tape would help? If the electrical tape is too soft, there is a lead tape made for weighting tennis racquet heads. Either would be a single use proposition, but should clean up easily with alcohol or adhesive remover.

Here's a link for the racquet tape:
Gamma lead tape

There's another brand, Babolat, but I think the Gamma tape is a little thinner and may be better suited.