I ordered some Radon Zombies from Pulp Figures. I primed them with Army Painter matte black:
For the base coat on the 'uniform' I made a mix of equal parts DecoArt Americana Slate Grey, DecoArt Americana Desert Turquoise, and Vallejo Thinner Medium. I also added a drop of water. The thinner medium is a great way to get your paint to flow, thin it out without separating and clumping the pigment, and get smooth coverage.
When doing custom colors I find it helpful to get little painting pots and mix the colors in them. That way if you need to touch-up a spot you have the exact color ready to go.
More to come....