I wish that I had taken pictures of the two cars that I did paint in black primer with 2 coats of urethane clear coat. They were the 61 Impala and 64 Plymouth that I built for Lindberg models. They were both on display at the Chicago hobby show. My technique (learned from master painter Steve Goldman) is to lay just enough paint to get an even color coat and then brighten it up with clear. I don't do wet coats of color at all. AND, if you lay the clear well enough, you don't even have to polish it! Look at my 58 Corvette. No polish at all, just straight up clear. I am finishing up a Nissan 350Z and will be posting pic's in a day or two that is not polished at all and is miles deep with 2 coats of Urethane.
James
PS: Steve, do you want to chime in on this one?