I'm lvl 97 right now and i know that i've done probably well close to over 1000 or so, but most of the time if you want assured luck (just because usually its what my friends do apparently) save your free draws till you have 10 or more seal scrolls, i pulled Danzo literally just yesterday on New Year's Eve and it was because i drew 10 and saved up my free draws, all i can say is best of luck, only a few people in my server dont have mei (Me Included), but everyone has shisui somehow.

My first rare, guess who ?