Kinser I use CA glue on top of all my cars. I use my finger and spread the glue out and let it dry then sand down to smooth surface and paint. It works real well for me and the glue helps strengthen the wood.
my natural wood cars I use min wax sanding sealer apply with a foam brush then several coats of polyurethane 1st then lightly sand with 600 grit sand paper between coats of polyurethane