Nice piece. If you want a fairly effective shading for his recesses, use a GW wash. Baal Red is pretty effective. It'll give it a good tone, and it really won't slow down the mass turn out of Blood Angel killing machines.
Looks like you have a really good start on it. Try highlighting with a little orange and shading with a darker red (red + very little blue will give you a darker tone without looking dull). You are on the right track, it is very clean. It just needs a little more TLC!