I use a Sakura brand "Paint pen" most of the time..I have a dip pen and India ink that works well too. When I used MinWax Spar Urethane I first finished the bow then 2 days later I wrote specs on the lower limb and lightly sprayed finish over it. I just started using Krystal dull from Big Jim. The Krystal dries in 20 minutes, I wrote specs between coats 2 and 3..