Tom, I use the reducer from Napa and it is the medium dry reducer. I've not had any issues using the reducer with Testors paints. I use the 1/4 oz. bottles and thin them down with the reducer. I'll put about a 1/4 inch of paint in the bottle and the rest is reducer. Now, this is very thin and I usually spray a few light coats like Donn does. I spray with between 10 and 18 lbs. of air. I do spray continuously starting from the top and then the front, then back and last the sides and then go over the model the same way until it is covered. Then I'll let it dry. That's all that I do. Most of the time I will spray the clear over the model after it has dried. But there are some times that I don't spray any clear. Like, if I'm looking for the shine of the 50'and 60's. That's about it.
Rich, I use Future floor polish instead of enamel clear for my clear coats. Future is sold now as Pledge with Future shine I'm told and should be in any supper market or Wall Mart.