Hi Chris,
Yes, the numbering was done by eye. The dial I mentioned earlier was re-engraved with 40 lines representing thousandths, and needed numbering 0, 10, 20, 30 against the four long "tens" lines. Once in the jig, I couldn't see those lines properly, so I used a felt-tip on the edge of the dial to help with alignment. The 0 was easy, but each double digit was done with fingers crossed that the two numbers e.g. "1" and "0" would be spaced nicely. I recall using a bit of carbon paper and finger pressure on the number punch to check; because of the curved surface, that only left a mark at the top and bottom of each digit, but it helped.
That dial was steel, but ally is easier to engrave and stamp.
Andy