I have never read so much mis-information.
Laquer and enamel? What is this, the 1950's?
Go to the auto paint store (or web site) and read the PPG literature which is available for all of their products. Read about PPG DP primers. Fill and surface after priming.
The best custom painter in ths U.S. is Charlie Hutton. He uses PPG products including PPG waterborne paints. Fantastic stuff.