For black background gauges, I have used a white or silver colored pencil to highlight the raised numbers, etc., followed by red/orange/yellow for the pointers.
FWIW, the Glosscote enamel (at least the rattle cans) has a tendency to turn yellow over time. I have a couple of silver builds from the mid 1970s that now look like GM Spring Green. I wouldn't expect the bottles to behave differently.
We just started watching the new American Horror Story "Double Feature". It plays into this with a "pill" that makes you absolutely brilliant at whatever you are trying to do instantly, but it has nasty side effects.
Well yeah, Dad painted my first few for me, then I was allowed to try. In the name of economy, I learned to stretch a single 69 cent can of Testors to as many as three bodies, LOL. The 5 and Dime also had Pactra, and I really liked them.