Karl,
I would spray Hi Build epoxy undercoat after it is faired and then rub that back with wet and dry 240 grit. The hi build will further improve an already well faired surface. Then spray it with polyurethane and cut the back with 600 and 1200 and then a cutting compound. When finishing the paint keep an eye on reflexions in the surface finish. Objects that can be seen in the reflexion on the surface will have their outlines sharpen and eventually become very crisp as the finish improves. I used a hand held shop fluro with very fine lines in the diffuser. Starts off as a mass of light and when finished you can count the fine lines of the diffuser in the reflexion.
At least that is how I finished the rudder plug for the
Farrier trimaran that I'm building. Gives a top finish.