Most hardware stores have smaller cans of paint, other option is a model store.

System 3 topcoat is available in a 4 ounce size.

Laszlo

Hello! it's Chris' son Eric.

 i work at Lowe's and we sell 'paint testers'. basically, when people are thinking of painting a room and don't know what colour to paint it, they can buy these tester cans. they are a little smaller than a can of pop and come in different types of paint and shades. 

 i'm not sure if there is an acceptable type of paint to put on over fiber glass (that's for my pops to figure out) but the option is there if you want to check it out.

and i'm going to assume that these tester cans aren't just a Lowe's thing... try your local hardware store and ask.

 hope that helps!

Eric