remove 1/2 the egg cups and put the first set on wire at day 20 and keep turning the 2nd batch until they get to day 20. 1 problem will be humidity difference at day 20 of first batch. You may drown the others
You can't leave the egg turner in the bator while chicks are hatching,or you take a chance on crushing a chick and damage the turner.I don't think 3 days of high humidity will harm the others as long as you get it back down after the first batch has hatched.