[Paul Workman]

The mask looks interesting; might give it a try.

I found using an artist's brush and acetone (aka fingernail polish remover) was the trick (for me).

After painting the recessed cavities and before the paint completely dried, stretching an old T-shirt dampened with the polish remover over my index finger, cut a perfect line between the flat surface and the vertical edges of the letters.

By avoiding much as possible getting too much paint smeared on the flat surfaces, I was able to paint the letters easily and quickly - knowing I could cut the letters with the acetone as a last step. Forget about trying to cut the letters with a steady hand and the atrist's brush: takes FOREVER! And, it was near impossible to cut the letters cleanly. Just paint 'em and cut 'em later is the ticket!