My advice, would be, paint in black. Highlight, with something of a black\\grey\\bleached bone mix. Then really really highlight the edges or everything pointy or sharp, or whatever with grey\\bleached bone (prolly more bleached than grey). THEN
glaze down with red and black, or black and green or red and purple, or ANY black ink + a color. This should dull your highlights down out of the grey zone, just make sure you re-highlight the tippy top sharp parts. Very cool