I did some playing today. Comparing side-to-side with two different paints. One I suspected wouldn't work, the other I hoped would work.
Top left corner is typical automotive paint. Any lacquer or enamel will have the same effect. It was an obvious negative effect on the ability of the SC to cool down. Test ran from 350 to 100 degrees.
Bottom right is something I may consider trying in the future. Results were positive on that one. But I won't tell you what it is until I see how it performs and holds up on the car.
Long story short, I'll get data up sometime later tonight.