RE: finishing problems
The backside of the vinyl stencils is labeled GERBERMASK. That type works fine.
I apply the basecoat first, which has been Acrylic Enamel. After this is dry it is wet sanded with wet-and-dry sandpaper, used wet.
The surface is then cleaned.
Stencils are applied.
I've had best luck using Krylon (gloss black) for the trim. Spray a very light amount first. Let dry a few minutes. Spray a couple more light coats and let dry.
Remove the stencil immediately after the final coats are dry.
Krylon is not totally fuel proof, but will be fine unless fuel is applied directly on top.
Typically I feather in the trim with wet-and-dry sandpaper, used wet.
I then apply automotive clear coat over the top.