Skin tones were done in the same style as my other Orks.
The Rokkit packs are being painted separately. The Rokkit packs (unlike the Boyz) were given a white undercoat.
The Rokkit packs were painted with different colours of brown with red nose cones.
They were then given a wash of Chestnut Ink, Scorched Brown paint and water.
Here is a work in progress shot of four of the Stormboyz.