Process for estimating draft round in a keeper league

I’m trying to figure out a range of players that will be available in rounds in a 12 team standard keeper league (teams can keep up to 3 guys).
When 30-36 players are already off the board, i just figure that increasing the ADP by about 3 rounds is as close of a guesstimation as i can get for who will be going in what round…

Anyone have another process?? Thanks