When I airbrush Future, I try to apply my first two coats in a nice mist covering. In effect, I am sneaking up on it and providing a good base for the final wet coats. You need to be careful as the stuff will run quickly! I use a dual action Air Brush so that is minimized some. I do not dry Future coats with the hair dryer as that causes a grainy finish. I usually wait a day or two between coats. The third and fourth coats I lay on wet. After another couple days of drying, I will rub out the Future finish with Meguiers #7 or fine polishing compounds, if needed.
In my previous post, the #31 Lumina and the #28 Texaco both had Future finishes to seal the decals. The #28 was brush coated and polished. The Lumina was the better effort (airbrushed). Not certain if you ever saw the write up about applying Future to models? Check out the site at the link, it is full of great information. Hope this is helpful!
http://www.swannysmodels.com/TheCompleteFuture.html