For sealing and paint, I'd suggest sealing with epoxy fiberglass resin (thinned if you'd like to save a bit of weight). I've used epoxy paints before, and while it's possible to get a good finish, to do so you have to spray them, and besides the super toxic fumes, it makes cleaning your paint gun a huge hassle as well. The best looking paint will be automotive base/clearcoat, but it will also be the most expensive. You can also get very good results from a rattle can with the right paint and prep, and an even better, fuel proof finish if you top the paint with a 2 part clear coat like 2k