Does mask type determine max humidity?

[RNeil]

You will get rain-out if the air temperature drops below the dew point, which is a function of the humidity. If your machine is like my F&P Icon+, you don't set the humidity directly. You set the temperature of the water. The air passes over the water and picks up more humidity if the water is warmer. If you have higher leakage, the air has less time to pick up humidity.
The mask affects leakage, which affects humidity.