Watco Teak oil is a natural finish, no stain in it. On light colored boards it will give an amber look to the wood. Sand with 320 grit between coats of spar urethane to get the bubbles and imperfections out. The whole board should have a dull finish, then apply another coat of urethane. I have some photos on photobucket without the watco and with the watco if you want to take a look. I am using cherry and purpleheart wood. Can really see the difference.
http://s159.photobucket.com/albums/t160/sworden73/