I believe the best wahy to prep the boards is to use Seasonite. Seasonite will a crystaline surface on all the pore walls. On oak it will work within a short period of time because of the porosity of the wood. You can soak the boards in the seasonite for a couple hours then let them dry. The best finish to put on top and bottom is clear marine epoxy finish if you want to see the wood. You must do top and bottom. Seasonite will work by itself but a top coating will give a lasting protection to the top.
