Thanks Marc. Caucasian? A bit on the dark side? Your formula looks complicated. I'll give it a try.
When mixing skin tone I just put some white, yellow ochre, cadmium red/Venetian red, dark umber and Van Dyke brown out and mix it into a base colour.
To that mix I add more white for the highlights and more brown for the shadows. Basically that's it. And when dry I line with dark umber/Van Dyke brown.
Cheers Paul