Hi vincentm,
For the metal parts I used Gunze MR. Metal Color paints.
Before laying them painted with black paint, preferably glossy, but and Matt is good for small details.
I work with a brush and work with these paints requires little training.
Otherwise work with airbrush far as I know are perfect.
When dry, I make oil wash.
Well it is, I hope I've been helpful.
Best Regards
Hristo