The reason I used that combo was because when I started painting in '65 all of the custom colors were lacquer, and all production colors were available in lacquer. There was no hardener to add to enamels, so you could not put a show finish on them. Lacquer was really the only option for custom work.

After I moved to Arizona in '75, I started having trouble getting a lacquer top coat to live very long. I did mostly Corvettes at that time. The expansion rate is about like aluminum, and we have 40 degree temperature swings every day, so cracking was also a problem. For a while, in the late '80s, I added a small percentage of flex agent to lacquer. That worked pretty well.

By the time I switched to urethane as a topcoat, I kept a few thousand dollars in lacquer inventory. Remember I do custom work, and a typical job has 10-30 colors in it. Also I had learned to do a consistently reliable job, every time, so I did NOT want to start the learning curve over.

What made me switch was the rapidly disappearing choice of colors. There are a few things that urethane will not do, but I needed the options that laquer no longer offers.

BTW, This Spring I saw an '88 Corvette in a local show, that I did in lacquer when it was new. It still looked great, and trophied that day. :-)