Air-brush varnish inside cabin

Has anyone tried using an air-brush sprayer to apply varnish to the woodwork inside the cabin ?

When I repainted my bulwarks in OZ, I used a small finger Binks paint sprayer, but I still had to resort to using an air-brush sprayer on some of the very hard to get to, places.

When I try to brush varnish the inside cabin verticle plywood surfaces, it is so difficult to prevent sags and runs around the trim joints.

Douglas, BCC Calliste