How to make medieval seal stamps with handles?

This year, I'm teaching Hands-On Medieval History at my kids' homeschool co-op. I would like the kids to make their own fancy medieval letters/documents, complete with seals. (See thread on making the sealing wax).

I like for my history students to learn as many historical skills as possible, and to do them as historically accurately as possible. Since my classes are only 50 minutes long, and I have students ranging from 5 to 15, I sometimes have to lower my bar. But, I want it as high as I can get it!

I really want my kids to do some metal working. Years back, I bought some metal stamps and pewter disks for the kids to design their own coin. This was a lot of fun for them!  I thought, "I wonder if we could make seal stamps the same way?"

My very limited metal working supplies, some coins the kids made, and a stamp I made the same way.

Close up of the pewter stamp and the wax imprint from it

My issues are these:

(A) Using only metal stamps is really limited! There's only so many designs you can make. I used a nail to make a heart design, but it's pretty jonky and annoying. Is there another way to carve/work the pewter disks so the kids can make whatever design they want?

(B) The disk by itself is pretty cool, but it'd be a lot neater if it had a handle, or even a little button loop. Is there a way the kids could add something to the back of these to make them more like stamps? Maybe there's a way they could sculpt their own backs?

Medieval seal matrixes (stamps) don't look like the modern, long-handled stamps that we usually envision, or even rings. They were usually worn on a cord around the neck

Sometimes they had short little handles.

Sometimes

I'm thinking the kids would rather have ones with cool handles, rather than just a loop.

Now, maybe there isn't a way to carve the metal. Maybe I should try to get soapstone instead? (There were some soapstone seal stamps, but most were metal). I definetly want to do soapstone carving this year (but, I'm hoping to do it with pewter casting, but that might not be feasible).

Ideas for the seal back/handle:

• Maybe for the back of the seal, the kids make it out of some non-historical material, like sculpy clay, and we just glue it to the pewter disk? What glue to use?
• My husband said maybe making it out of something like JB weld? Is that okay for kids to handle?
• Maybe I just get fat dowels and they glue it to the dowel? What glue to use?
• None of these seem good. Do you have any ideas?

I hope someone familiar with pewter work can chime in! I have no experience with it.
The times I've encountered the various JB weld products (helping husband on various repair projects), I seem to remember some pretty strong vapors/odors. Probably it depends on which of their products you're using, and the maturity of your students. I personally would be pretty hesitant to let them handle most of those products (especially before they've set). I think some of their stuff starts out putty-like, and some is more liquid glue-like.

This is not historically accurate experience, but I'll share just in case this sparks something for you, or for future seal-makers:
Several years ago I made some seals out of air-dry clay. They weren't medieval by any means, but they were functional. I rolled them into rough cylinders to make double-ended seals. About 2 1/2 to 3 inches long, as big around as a quarter or a bit smaller. They became their own handle. Since I stored them in a pouch, I didn't think about sculpting loops - but you probably could.

I carved some designs myself (directly into the clay), but what I liked best was pressing some interesting charms and buttons into the clay to make an impression. I may have oiled the buttons a bit to make them easier to remove from the uncured clay? With this method I didn't have to be so precise with my own designs, and they turned out sharper than my carvings once the clay had dried, if I remember right.

I think I would experiment to see how the clay behaves with the pewter without any adhesives. What if you "nested" the metal into the clay? Like - wrap the clay around the disk's edges a bit, and let it dry that way. Or to keep it all metal: use a different metal (wire of some sort?) to "cage" the disks and create a handle or loop?

I'm really interested to see what you come up with! This is a neat project - lots of layers of learning here!