Topic moved to Modelling and Painting 
They're tricky to get right being White and I can't say any of my ideas will help you at all because I'm dreadful at painting White at the best of times.
The only way I can think of would be Skull White basecoat with a black wash and highlight Skull White.
Or you could start with black and highlight Codex Grey, then Fortress Grey and then keep adding White for each extra highlight untill it's a pure Skull White highlight for the final highlight.
But you might want to see what other people say who actually have decent experience with White skintones, because as I say, I tend to avoid painting White
They're tricky to get right being White and I can't say any of my ideas will help you at all because I'm dreadful at painting White at the best of times.
The only way I can think of would be Skull White basecoat with a black wash and highlight Skull White.
Or you could start with black and highlight Codex Grey, then Fortress Grey and then keep adding White for each extra highlight untill it's a pure Skull White highlight for the final highlight.
But you might want to see what other people say who actually have decent experience with White skintones, because as I say, I tend to avoid painting White
