After much testing, we found that the Palmer body paint works best under our lighting setup. An even mix of about 1:1 paint and water applied with an air-brush, creates a nice, clear, uniform wash on the skin. It hides the skin enough to cover up all the specular highlights, but it is transparent enough to let the muscle, veins and skin texture show up through it.
In the images you cans see the red-tempura paint applied on the left side and the white body-paint on the right side. Clearly the white color responds better to the light and creates a soft diffuse surface.
We've ordered the same paint product from another brand -- Kryolan's which is a bit cheaper. The paints should be here early next week.