RE: PPG Concept temperature
I'm not an expert for sure, but I've been asking the same questions myself lately so I'll give you my take on what I've learned. The really harmful paint are the ones with the isocynates in it. This includes any PPG Concept or Omni paint that finises to a gloss. This means the clear coat (DCU 2021 for the Concept line) AND the gloss single stage Concept paints. Note that single stage refers to the fact that its all in one coat - the color and the gloss finish, not a base coat and clear coat (which is called two-stage), but the single stage Concept is still three parts, paint, hardner, and reducer (thinner). Basically, if you have to put a hardner in it to cure, its bad for you. Read the contents to be sure - isocynates = can kill you = bad...
As far as a base coat when you're going to top coat it with clear is concerned (the two-stage process), I've found that almost anything will work - but you better TEST it first to be sure. I've used Rustoleum spray paint from a can and the Omni base coat paints to go under the Concept clear. Both worked well although I think that the Omni base colors will hold up better against fading than the Rustoleum, but we'll see. I've also heard that some latex paints work as a base coat under the Concept clear, but I haven't tried it.
The actual base colors from PPG are single part. That is, you only mix them with thinner to spray on and they dry by having the solvent evaporate. They are very easy to paint and although you should be careful with them, they're not as bad for you as the two-part, isocynate-based stuff. These base colors finish to flat, not gloss and are not very durable until they are clear coated.
Like I said, the F-16 was painted with Omni base coat colors, the Aeroloft dry transfers were applied, and then the 2-part Concept 2021 clear was put over it all. It was so easy and worked so well that I'm probably going to use that for all my models from now on. I did however, decide to try the single-stage Concept colors on the Flash because most of the plane is going to remain the original white gelcoat, so clear coating the whole thing didn't make as much sense. We'll see how well they go on...