I went with 9 coats on mine, using Halmsman Spar Varnish. I consulted with my dads cousins husband, who is a professional woodworker about it, that was the product he suggest (he even gave a 1/2 quart of it). He suggested 8 coats, I went one more as I had some leftover. Took about 2 1/2 quarts total, my truck is longbed 1/2 ton.
