Hello Justin,
Actually I have been using real automotive clear lacquer. I was able to get an old quart of Sherwin Williams automotive lacquer about 10 years ago. I have been using that on most of my stuff. Today you could probably go to your local auto parts store and pick up a spray bomb of clear and decant the product into jar, then spray it through your airbrush. You wouldn't have to thin it. The thing with clear lacquer, you will not get a completely smooth or shiny surface strait out of the air brush. After you let the clear gas out for about a week, there is some wet sanding and polishing that needs to be done to get a super smooth and shiny surface. When I do my initial spraying I usually thin it a little more with super slow thinner. I use DuPont 3602. Unfortunately, I am not sure if you can get that any more. You may be able to order it from House of Color.
There are more steps on the sanding polishing thing, I wont get into now.
Hope this helps.
Frank