If I remember rightly (I'd have to dig my
WIP thread out, it's on here somewhere)...
Black undercoat. Zenithal pass with VMA Hemp, VMA Sand Yellow, VMA Sand, VGC Ivory.
Spot washes with agrax (devlan mud).
Edges with VGC Ivory.
Glaze with mix of black and sand for a warmish grey to smooth speckles in deep shade.