Never used Vallejo paints before. Can they be brush painted easily? And when airbrushing, what pressure settings work best and what thinner ratio?

Vallejo's Model Color range is designed for brush painting, they are excellent paints. For airbrushing you should try the Vallejo Model Air range, ready mixed and thinned for airbrushing- just put the paint in the airbrush and spray away. If you want to use the normal Model Color range to airbrush then you do need to thin them- Vallejo's own thinner works best although I can't tell you the ratio to use as I don't use the Model Color range for airbrushing. I would say that pressure settings depend on the airbrush and various other factors like what sort of finish you are after and whether you are doing a camo scheme etc- its best to experiment with a range of pressures to see what suits.

I just airbrushed the base color (their Games Line midnight blue) on a blanket for a 1/9 bust and their regular line black gray as the base color for a 54mm horse. Pressure was the same I use for enamels and the paint was simply thinned with distilled water. With the fine tip on my Badger 150, I was getting 1/16 inch lines and was able to paint around most of the horse tack with minimal overspray. The line between the bust's shirt and blanket will probably be masked to avooid overspray..then again the area wher the overspray is likely to be will be given shading by hand in the latter stages of teh painting.

As with using any new airbrush and/or paint, test this out on scrap, paint queen or sheet stock with an appropriate primer.