I don't have a LOT of experience with the epoxy paints, but I do paint a lot with Urethane's which are in the same general characteristics. If you can unmask before the paint starts to get stringy then I generally do that. If you wait say overnight,, the paint film gets so strong that it doesn't want to shear cleanly sometimes. It is far SAFER to pull masking off when the paint isnt wet, so you don't drag wet paint across the rest of the surface on accident, or get paint on your hands then touch something,, All that being said, I generally try to mask things so that I can pull the edge tape away from the fresh paint, leaving the paper on the surface to pull up later after its dry.
Hmm that may not make sense. try this when I mask up for a color, I use vinyl mask tape, 1/8 or 1/4 generally. Layout my design. Then I will mask the rest of the area with tape and paper leaving the paper about a 1/4 away from the vinyl tape. then lay another strip of vinyl masking tape to close-off between the paper masking and the outline separation masking. That way when you unmask, you can pull up the 1/4" and the actual edge masking leaving the paper in place to protect the rest of the plane from accidental drags and touches.