Saw this post after you emailed me. Mine is black and white with silver pearl.
The pearl is mixed into the clear. The minimum pearl needed for light colors is the same as the maximum needed for dark colors. This amount is like like 1 tsp. per mixed quart. I found this concentration to be perfect for the white, but too much for the dark. I would have prefered using the minimum light concentration for the white and the minimum dark concentration (like a ¼ pearl) for the black. Mine came out more charcoal/white, than black/white, as I originally intended.
This, however, would have required that I either use metallic paint instead or that I go through the process of painting the under coats, then masking for the pearl all over again. I suppose I could have sprayed the minimum concentration over the whole bike, let it dry and then mask the dark areas and spray a ¾-minimum light concentration.
I would really like to ask some veteran painters about their techniques some time. But that should be something to consider when you are doing this. In other words, don't expect a brilliant white pearl AND a deep black pearl with only a single pearl session. As far as I can tell, it has to be two sessions. I am also not certain how this would affect flash times and curing, since I used a special catalyzed urethane clear.
SOOO many details. But I can't wait to get a new place, a new booth and start painting again.