Alien Color Test

With HR Giger's painting NYCII as inspiration, I have begun testing colors for the Aliens project.
While this is not one of the paintings Giger used while designing the original "Alien" creature, I find the color depth and unique curved gloss elements to be inspiring.  To this end, I have been experimenting with these colors on a few random miniatures. 

Here is the treatment I used:
Black primer
Overbrush turquoise
Light drybrush drab olive
Light drybrush middle metallic
Dark brown/black dip

Here are the results:

The shoulderpad in the photo has received an additional spot treatment.  I mixed water effects with a tiny touch of white, and layered that on to the curved plate.  I plan to use a similar treatment on the curved and smooth heads of the Aliens.

On the models themselves, I am hoping to airbrush at least one of the layers of color.  I have had some success getting a top-down lighting effect glow, so I think there is potential for some interesting work. 

I only have about 10 models left to build at this point, and I am itching to get painting.

I would appreciate any feedback on the colors.