Are you building a new home?
Check out PAINTING Guy's mobile interior door painting system.
They set up and spray both sides of a door using a rotating spray system. They are able to rack 32 doors in small spaces where they hang to dry until ready to install.
This drying system prevents doors from warping while drying because they are balanced , not leaning up against anything. Door warping is more common today because of the thin "paper-like" material used to build panel doors today.