DK,

As with any paint............dry and cured are not the same. Vallejo can be dry to the touch in 5mins, but about 24hrs to cure.

When thinning in the airbrush, thinner first....always.

Primer.....always.

Vigorously shake the bottle before using....always.

If you find it isn't mixing up enough in the bottle, the dropper top comes off, so you can stick in your favorite paint stirrer (Tamiya Stir stick is my preference).

If you are going to use water to thin for airbrushing....go to your local pharmacy, super market, and get yourself a gallon of distilled water. While tap water will work, the minerals in the water can react with the paint, and can affect its drying, smoothness, and even leave mineral deposits on the paint once dry.

Haven't heard of a couple of drops of future with the paint mix....I would say only if you want to change the properties of the color from a matt to a gloss or semi-gloss (all the colors are matt, unless they say otherwise, of which there are only 2 gloss colors in the Model Color line), Vallejo makes Gloss, Semi-Gloss, and Matt varnishes and mediums to be used with the paint.

Yes you will go through thinner quickly, as some colors may require as much as 80-85% thinner to get them to spray properly.

When I said there was a steeper learning curve to thinning Vallejo to airbrush, I wasn't kidding. Everything you know about thinning Tamiya for airbrushing...throw it out the window, and start fresh. The results however are worth it.

Not all colors are the same, as for some colors it takes more or less pigment, to make a certain color.

For something like white or grey, you won't need to thin it as much, however for blues and reds, you will have to thin more than usual. There is no set ratio like Tamiya (pretty much 50/50 thinner and paint will spray any Tamiya), consistency of skim milk is the best advice I can give you.