Eventhough I'm still not sure about the final paint scheme, I decided to use Astonomican Grey as base color - this area is more or less interior, so it won't interfere too much with the final outer paint scheme.
To emphasize the steampunk topic even more, I decided to give some of the pieces a wooden surface.
Together with the brass, I think this looks pretty steampunk, doesn't it?
For the other pieces I kept the paint pattern of black base coat, drybrushed with Boltgun and some items painted in Tin Biz and Dwarf Bronze.
The plotting table painted.
I hope the greenish outline will give it a kind of holographic effect, while the wooden surface of the rim will maintain the steampunk feeling.
All pieces painted and in place.