I used Testors model paint to fill in the design. I let it dry then used a some cleaning patches with Hoppes 9 to work the excess paint. You don;t want to down to hard because it will remove the paint from the design. Just ahrd enough to clean the flat surfaces. Mine have been on for over 4 months and even with wipe downs and oilings the paint is still on there. Did it to a Tactical Innovations lower though, but the process would be the same.
Esrice, you posted that vid as I was typing this responce out..LOL