As a mater of fact, your 1/24 scale shells are wearing some Createx AutoAir!
I've seen people paint full cars with this stuff, but mostly used for graphics. Createx has upgraded their paint formula over the past year or so making it much stronger than before and even adding some base coat colors. You will still need to clear the paint with a good quality clear. As the weather warm up, I'll be adding some graphics to my daily driver (914/6). I'll use the new formula AutoAir for the graphics, One Shot for the stripping, and HOK for the clear.
BearAir.com and
CoastAirBrush.com have everything you need.