I've used Koveral for years as it super easy to apply with the Stixit adhesive and it makes a great bag to carry all the parts home in. For a quick and cheap finish on them I use Minwax water based polycrylic applied with a foam brush, spray on some Rustoleum for trim then give the parts that will get fuel with spray can Minwax polyurethane. It works out at about the same weight as nylon or heavy silk but much tougher and if you do manage to dent it heat tightens it right up again.