When I use the VHT paint, I let it sit for maybe 15 minutes so it gets a little tacky.(less likely to run when heat applied) Then I hit it with a heat gun. Make sure to move the heat around and don't have it set on high air speed. One area will start to wrinkle and you can follow the leading edge along with the head gun. If you hold the heat in one spot too long it will bubble.

You don't have to use heat if you don't want to. When redoing my plastic Challenger heater controls, I just let the parts sit in the sun.