I've been using PPGs DBC basecoat but DBU is good also and has a reactive reducer so the basecoat is kind of hardened.It's great when you start getting thick on the basecoat,but the metalics get grainy and you can't keep what's already reduced.If you use DBU in metalics or colors with alot of pearl,don't tack off the base with a tack rag because it'll pull threads from the rag.The best way I've found is use a low pressure blower (like 10lbs) and a freshly washed and dried hand to lightly wipe the surface off.Sikkens is killer from what some friends say,but I haven't tried it yet and my understanding is they are limited when you want to play with candies and pearls,so you need a mixing system to make them yourself.House of Color makes good stuff too.
If your tanks are primed with lacquer,it needs to come off before you put any urethane topcoats on or you could have problems.
