Has anyone had experience painting luster dust mixed with alcohol on modeling chocolate? Does it just bead up?
Once your modeling chocolate is set - - preferably overnight, but at least several hours - - treat it the same as fondant. It will react the same with painting, coloring, flavoring, storing, etc.
AAlthough in my experience I have had to paint the modelling chocolate with oil-based colours, as the water-based colours (either straight or mixed with alcohol) tended to bead. I've also seen airbrush colours bead on modelling chocolate - it was so cool, it was used to make dragon skin so it was meant to be patchy. Definitely I haven't been able to get an even smooth coat with water-based colours but no issue at all with oil-based.
Agree with winniemog, you want to use the colors made for chocolate as they are oil based. If you don't have them try painting a thin layer of white first, let it dry, then paint you color over it.