You can always use automotive paints. But you can also use Matthews Sign paints - Signage/architectural specs 70,000 colour formulas available, including all pantone colours, 3M vinyls (many Avery, Mactac, Oracal as well) and a long list of corporate spec'd colours. Colours reproduce very accurately in small quantities (i.e., 1/10th of a pint).
1.5-1.8 tip sets Gravity Feed
1.2-1.3 Pressure Feed
Suggested Guns Mathews Sign and Placard Paints