I kicked around a couple of ideas for the Aquila color on the inducted Space Wolves Berzerker, and in the end decided I'd see what would happen with taking one of my usual bone basecoat color and adding metallic medium to it. A little bit of highlighting, a wash or two of the same blood colors I'm using for the Berzerker armor, basecoating the brass trim, and some tidying/clarifying of the beard brings things to this point:
Specifically, I used 1:1 GW Vomit Brown/VMC Metallic Medium as a basecoat for the SW chest decoration, shaded a bit with GW Gryphonne Sepia, and then brushed on a few shading washes of the dried blood color I'm using on the non-grey parts of his armor.
The other Berzerker has his armor painted (not highlighted) and the basecoat applied on the brass trim. I'd ideally like to do something for the clawed hand along the color of this guy's face: http://www.coolminiornot.com/202765
I'm having a hard time trying to figure out the actual colors of the face on the Bloodletter CMON link I posted - it's an older paintjob, so I'm assuming some sort of grey/Bleached Bone mixture highlighted up to white. If I were to replicate it, maybe GW Dheneb Stone/grey highlighted up through Bleached Bone > Skull White, or do you all suppose that would that look a little wonky?