I have some of Eduard’s masks on the way, and as soon as I get them, I’ll let you know how they work.
A technique that I have used in the past is to mask off a rectangle the size of the character that you want, and just fill it in by hand. The mask is just for reference, another words, you don’t want to go any bigger than that. Then move on to the next character with the same sized mask.
As usual I would suggest trying this out on scrap first.
hope this helps you
edog