You don't need to dip a second time unless you want your painted frames finish to be glossy as the clear canopy.
Dip prior as mentioned so you can return to a starting point of a bare canopy piece if you muck it up while working with it.
Painting the tape just allows one to see it easier...after all its not called invisible for nothing! If you're going to go through the effort of painting the tape, why not cut it into the piece you need to use as the framing instead of a masking.
Commercial masks are easy and durable to use. You can soften the mask, with a little warmth to more easily remove and reuse it on a second model...though returning the piece to the carrier paper is an option, I find going from one project to the next mo'better.
The commercial precut masks also offer an distinct advantage...little or no residue to remove compared to most tapes.