I see nothing about finishing - clear nitrate or what? Or nothing?

From : Don Stackhouse

Nothing at all is best. Weight is EVERYTHING on these models, and any finishes should be kept to an absolute minimum. For any coloring we recommend permanent felt markers, they're simple, quick, and add almost no weight. Another slightly heavier alternative for covering large areas is airbrush paint (the pigments in that are more opaque than for brush paint, so it can cover better with less paint), but just slightly dampen a paper towel wipe it on instead of spraying. This will take much less paint and save weight. The Corsair in the photos on our website was painted this way.

Don Stackhouse
DJ Aerotech