The challenge you'll have with something like a swing arm is, if it pulls loose, you'll have to re-do it. And in order for it to look good, you'll probably have to pull your swing arm off which is more work than its worth just for Plastidip. It's a cool product, but I don't think it's a long term solution for what you're trying to do. Ive used it enough to have some basic experience with it.
Certain places its fun to mess around with, easily accessible places/parts, but I don't know that I'd do an entire swing arm. Probably not what you wanted to hear Big Twin, but again just my opinion. Try it out on some other parts first, like frame rails, or plastics, etc.