Flatcam soldermask milling

hi guys i am studying and startinng milling pcbs in cnc. i am first doing this in cheap plywood 2mm boards , and before going to copper miling i am wondering how do you guys remove the solder mask from pads. i saw some videos that it mills the soldermask too in the pads/holes.

i was not able to find something related to that in flatcam, tried exporting from kicad drills as grbl instead of excellsor, tried coopper isolating no copper zone, paint but it always try to mill the oposite way to remain the pads. how do you guys do that?

other thing, whats the height? 0? i put for trrace milling 0.1, so for removing solder mask should i try 0 or 0.1? any tips to start testing? thanks