I'm using acrylic enamel and am painting the panel truck grey. I'm going to paint the top first and seperately, as I will have scaffolding setup. On the front I can cut it off where the drip rail meets the belt line, the back is a problem though. Mostly because this is my first paint job.

I have about 10 inches of body I want to tape off, between the end of the side drip rail to connect with rear door drip rail. When I'm ready to paint the bottom section, do I try to tape right up to the new paint vertical edge or do I have to back my tape off and color sand the ridge?