I saw a boat at the Wooden Boat show in St. Michaels MD that had a neat solution to the nail head problem. The builder had counter sunk the nails below the surface of the deck. He was careful to place all the nails an equal distance from the edge of the deck. Then to routed a groove about 5/16in wide and probably less than 1 ply deep right over the nailheads. He filled the groove with colored (black) epoxy. The effect was a nice accent stripe all around the edge of the deck.