Any of the varnishes over in the sailnet store will work. One of the industries top products is the Epifanies clear
varnish, I have seen wonderful results from this product. My next in place
varnish job I intend on using Epifanies wood finish, just like the idea of multiple coats with out sanding if I'm not removing the wood to work on it. Maybe someone else can comment on their wood finish compared to the clear varnish. Application is real important factor too. Here is a link to a page where Don Casey has a few articles about varnish ( and a few other things), some good reading
BoatUS.com: Don Casey Library , best of luck to you.
Dan