is it a medium or slow or fast reducer? Have you tried to thin it with mineral spirits instead of thinner? It works very well.
You won't something that is a sloooow evaperation rate. Don't hold the (HVLP)gun any farther than 10" away from the surface. You just have to play around with it and spray some scrap body panels to get the right mixture and technique. Good thing is:
1)Gallon of Thinner $5 / Mineral Spririts $2
2)Gallon of JD Paint $25
If you do screw it up....sand it off and try something different. These are just my experiences with it, it might or might not work for you, but everybody in my circle that has used it has had great results.
Good Luck....Post Pics when you are done.