Your project reminds one similar idea made by 21e15.com, but I think they are using even smaller size letters.
It's amazing to see that just a single washer can be used to store all 12 or 24 seed words.
Another thing I like is the fact they are offering titanium and standard Stainless Steel washers.
Size they are using for washers is very similar to coin shape, but I think their kits are a bit more expensive.


https://www.21e15.com/