I got lucky painting these because I hit the exact shade of Red I was shooting for on the first try. Here is my painting recipe. I started with a black undercoat.
For painting the armor, I base coated it with Mechrite Red. I followed that with a 50/50 mix of Blood Red and Water. Then I washed it with Baal Red. To accent the armor pieces, I painted all the areas in between them with Chaos Black and then I lined all the recessed areas of the armor, including around the edge of the shoulder pads, with Badab Black and a very thin brush.
For the helmets, I used Iyanden Darksun, followed by Golden Yellow and then washed with Gryphonne Sepia. I then highlighted the edges with Sunburst Yellow. The eyes were painted with Knarloc Green, then washed with Thraka Green.
All the metal areas where painted with Boltgun Metal and then washed with Badab Black.
I am very happy with the way these models turned out, so now I can start assembly line painting the rest of my army.