although I know its best to lay things flat to spray, , these door holders from rockler are fabulous.
I dont have the room to lay out 10 doors and a bunch of drawer fronts when I spray.
with these holders, and the plugs to cover the other hinge holes, I can hang up as many as I need too, space is no problem, hanging them from a pipe I use for clamping, or just hanging them on the garage door track to dry.
You put them into the hinge cup hole, (35mm), and twist them, and they lock in.
for me, super convenient, a long term investment, worth the money.
(I use a chain so I can adjust the doors to hang at any height according to the size of the door and where I want it positioned in front of me.)