[deuce_roadster]

Most of the Woodie owners I know use a modern marine spar varnish on their cars which gives a stock looking finish. Urethane clear coats in my opinion give an ultra shiny plastic look to the wood and is most often seen on street rods.
A Woodie restorer taught me how he did the cars that came through his shop. He used Z-Spar Captains marine spar varnish. Brushed it (or sprayed) on after heating it up on a hotplate, sanded between coats. It took 4 to 5 coats before I was satisfied with the finish on my 40 wagon which has not lost any points on the concourse due to the finish.
One of the aspects of the marine products is that I think they have more UV protection built in. I also think the varnish smells pleasant. There are pictures of the car in my public albums if you want to see what that looks like. My buddy and I made all new wood for his and my car.
Just like a wooden sailboat, all the wood needs to be varnished.