Brian, I very seldom go in this direction but the guy at the paint store that tells you to put lacquer thinner in enamel is a MORON and should NOT be trusted with ANYTHING in the paint business.
You NEVER put lacquer thinner in enamel. Lacquer thinner flashes very fast and you will loose gloss, and adhesion. That type of "Junior Chemist" advice is what causes problems for you and the paint manufactures reputation. It makes me sick to think that some MORON behind a counter is telling people that. You can tell him that for me. The paint manufacture that he "represents" (they rip thier hair out over MORONS like that) would be happy to have him at one of their "Product knowledge" courses at their tech schools. They usually pay the tuition, meals and sometimes even the hotel room. THAT is how important teaching proper information is to them.
PKNAUTH, Acrylic enamel is not rocket science no viscosity cup is needed. MARTIN SENOUR and DuPont are two different things so you will get different info there. But as far as what the guy told you and what is on the can is simple, he is talking "old school" and the label is talking "new school" LOL. Because of the VOC rules in the "National rule" the solvent (VOC) had to be reduced. It works like that but can be a little harder to spray. If you add a little more reducer (closer to the recommendation of 3:1) you will have an easier to work with mix.
I have not shot Centari in YEARS and I hate to tell you to do anything different from the directions on the can. I would spray it out and see at 8:2. If you are having a hard time to get it smooth make it 7:2 or even down to the 3:1 (6:2 and 3:1 are the same). Acrylic enamel is pretty forgiving in this department, you don't have to have a specific amount for it to work, the "window" is pretty wide.
What gun and tip size are you using?
