It's hard to compute since there are times that I make a signature halfway then stop and continue the next day.. The shortest time I did was around 25 minutes (I know this because I had a Cooking Master Boy episode on my TV XD) and the longest I've ever alloted was around 3 hours, because I kept messing up with brushing.

im really pleased with how it came out though. Its completely different from anything ive ever done on a tag before. Thats probadly the longest ive worked on one in my life ^^