I've been using quite a bit of 4200 and 5200. After application of the 5200 and things are drawn tight...hatches, fittings, thru-hulls, screws, rivets, etc. I take some acetone on a cotton t-shirt and wipe around the item in question. The only 5200 left is the barely visible and inaccessible white ring of 5200. At that point, you shouldn't be able to tell if it's tacky. That's when I'd proceed with your paint plan.
