I did the Leadbelcher/Nightshade first so that I could be a bit fast and sloppy about it. With that done I completed the deepest recesses, which happen to be the skin. Then I broke the unit into five batches of five models and base coated each with a different color beard. Rhinox Hide for brunett, Mournfang Brown for gingers, Balor Brown for blonde, Mechanicus Standard Grey for grey and black for, well, black.