There is a new sheriff in town! I have been investigating these months, and I have come up with a new solution... the BitJig M14.
Now we can engrave 44mm washers, being able to engrave each side with up to 12 words, so 24 words on a single washer, which is not big at all.
Here you have a render:

And here you have a test


As you can see you can engrave up to 24 slots per row, 3 rows with 24 slots each, so each slots can get the proper numers and letters:
01AAAA02BBBB03CCCC04DDDD
05EEEE06FFFF07GGGG08HHHH
09JJJJ10KKKK11LLLL12MMMM
There is enough room to engrave the letters and numbers, and as you can see it is enough with just 4 letters per word.
I will upload it to
https://hideyourkeys.io/ next week, and also will try to release a free version without the anvil.