In years long past, when polyester resin was used instead of epoxy resin, some types of wood needed to be sealed with shellac or lacquer before applying the fiberglass. an ordinary varnish sits on the surface of the wood while shellac is much thinner and soaks deeply into the wood fibers. You might consider shellac as a sealer under your epoxy, but I don't think it is necessary to so this in order to obtain the finish you wish.

Use a few scrap strips as samples and test these with epoxy. Sand (or scrape) the strips just as you did your hull, mix up a very small bath of epoxy (just a few drops is all you'll need) and spread the resin on the wood. Let this harden for a day or two and you'll have a great idea of how the grain will be "developed" by the resin soaking into the softer, open-pored areas of the wood. It looks a lot like a varnish or polyurethane finish. If you want something that shows more contrast, consider mixing a small amount of a black or dark brown tint to your first coat of epoxy. Apply this very thinly and then wipe off whatever is sitting on the surface with a rag. The pigmented epoxy should soak into the soft wood areas like a stain. The use of the rag to remove excess epoxy, and some light sanding later can lighten this effect.

Water-based stains will also work as long as they are completely dry before you apply the epoxy resin.

Hope this helps

PGJ