Well it really depends on what you used as your paint coats. Automotive lacquer is very hot and will blister acrylic and enamel model paints and can melt plastic.
I do not use many gloss top coats but for flat coats, my clear of choice is Testors Clear Flat Lacquer Top Coat. It's a lacquer but is airbrushable and dries instantly, so there is no chance of it softening and marring the paint layers. I like it because it dries dead flat all the time every time and does not make dark colors look light or pastel. I recently used some Testors Acryl acrylic clear flat in a pinch and its "okay" but not as ultra dead flat and it will turn black into a hazy blue grey color.
For gloss coats I have used Future, usually brushed on in a couple of coats and allowed to level out on its own.