If you're replacing a condenser head with a diffusion head, it's easy to make comparison test prints and see how much more magenta filtration you need for printing with the color head.(posted 8670 days ago)If you're taking a recommended development time and trying to adjust that without testing, forget it.
Generally speaking, negs that print well with no filtration on a condenser enlarger will need 25M-40M with a color head, but since condenser heads are _way_ different in what contrast each gives and color heads aren't calibrated to anything other than arbitrary steps, in reality all bets are off.