Has anyone tried the Testors color changng paints for cars?
No.
But, I just tried TurboDork (that’s the brand name…it’s a fantasy line) color shift paints and they worked REALLY well. BUUUUUT, the ONLY thing I could find that thinned them well was Vallejo Flow Improver. Anything else and they wouldn’t airbrush.
If you want to give them a try, they came out really well for me.
I have used Avon colour shift nail polish to paint vehicles. It sprays well with cheap lacquer thinner. The results are quite acceptable.