Did you read my full comment? I give full details on the mathematics behind what will happen if the manufacturer uses 0 clearance. (There is no way around.) And i detailed what the alternative is.
And at the end i gave details under which circumstances you can accept which of the two:
I don’t know what the board fabrication and assembly houses will use for their numbers. I only know that KiCad Gerbers sent to OSHPark with 0/0 for SolderMask Clearance and Spacing were manufactured as expected on “Stupid Small Parts”.
An On-Shore assembly house gave me an initial quote for NREs of 1_KIlo_Buck to fix some of the KiCad data that is going to be put into their automation machines; it seems that they currently accept Eagle and Altium files normally.
@Rene_Poschl There is no attempt to argue with you from my side of the screen. I know that you are right that different Fab Houses have different tolerances and capabilities. All my comment was meant to help the OP stating using OSHPark.
Disclaimer: I do not receive any compensation, I am just another Purple Board Fan. It is GREAT to get “exactly” what you asked for when learning how to do this PCB_Design_Thing.
If someone is really curios about the process, it is because the different colors of SolderMask require different clearance settings; due to viscosity and cure time.