I would run plenty of Mocks to see where players fall. I have never played in a league this large, however I can assume that RBs would still be king. QBs would be a hot commodity, since I can't think of 20 solid QBs. However I would expect a RB,WR,WR,QB or RB,WR,QB,WR to serve you well. Execute a few mock drafts with: League Master
or Draft Dominator
and report back with your findings.