I don't know why old timers keep saying to use Lacquer. There is good reason they phased it out. My local paint jobbers don't even sell the stuff.
If you want a paint job that will last you WILL NOT seal it and spray anything over lacquer, anything painted with it should be stripped and completely removed before spraying anything else.
Lacquer never completely hardens under the clear. That is why the clear cracks and lets it dry out and then it appears chalky. It's a new century, people need to really let lacquer go. They didn't even teach us lacquer when I was auto school. We used only the newer urethanes.