You could try a C.S. Osbourne or a Vergez Blanchard. I have the CSO and its working but there have been a few times I was afraid it was going to bend which is to say that it needs some work to get it smooth and passing through leather easily. I don't have a VB due to price. I haven't yet ascended high enough on the skill tree to justify the cost of VB stuff yet but I can only imagine they are the best.
The force is strong with that piece. Brilliant idea for whoever came up with implementing all the pieces into the Mayan calendar style. Pretty good idea burning it onto leather too!
I had no idea the rarity of the stuff but now I can certainly understand the nerves. I'd have ham-fisted that reindeer leather into mush; if a little tension on the thread works, a lot of tension has got to work better right? :/
Those look beautiful and congrats on being able to handle unobtainium not only without damage but with beauty as well.