Why don't you try dimensional fabric paint? I've been using that for years, mostly on masters of small scale AFV, and it's just great. Apply with a very fine cocktail stick. It takes a bit of practice to get a series of 'rivets' of the same size, though! But if you're not happy with them, just remove them by scrapping them off with another stick. Once you're happy with them, seal them with a thin coat of Johnson's Future.
There are many brands to chose from and there are many colours too! The colour is important: always work with a paint that will show up against your model' surface. I currently use the 'Bright Red Shiny' from PLAID.
It's also inexpensive - just a few bucks per tube, and will last forever..!
Good luck.
Domi