Cadet Chuck
My motto is "Future is for floors, not models." I always suggest people use a clear lacquer or acrylic intended for use on plastic models, from a manufacturer who specializes in hobby paints.
I disagree, but suum quique, or "To each, his own." I use Future to make clear parts clearer, and as a prep coat for decals. Future is also one of the things I use to adhere clear parts, along with white glue or styrene glue, depending on the situation. I also use it as a clear sealer coat on my toy soldiers, even those painted with gloss enamels.
As for application, as plasticjunkie noted, Future is self-leveling, and yes, can be applied with an airbrush or by hand. I have used both methods. When airbrushing it, I apply it undiluted, in thin coats, at about 15 psi. Whether airbrushing or hand-brushing, if you get runs, drips or pooling, you can use a diluted ammonia solution (eg, glass cleaning solutions like Windex) to dissolve the acrylic again and then let it level and cure.
As a prep for decals, I have also used Future as a setting solution--though I do use Solvaset, too. Along with applying it as a general gloss base for decaling, I have also spot-applied it with a brush to the place where the decal will go, then laid the decal down, and put a little more Future over it. All of this helps fill the tiny pits or voids in the surface, where air can get trapped and cause silvering with any clear parts of a decal.
I applied DullCote over it, and I've never had any problems with the matte lacquer over Future.
I do understand the idea of buying a product made by a manufacturer specifically for our application. For example, I use Tamiya acrylics, and I only use Tamiya's acrylic thinner with their paints. But I also use craft store acrylics, which are not made with scale modeling in mind. The point is, if you're curious, try it and see how it works, and if you can make it work in your application, then why not?
Best regards,
Brad