Any of the grey colours added to flesh tones will work.
Glazes of green & yellow away from open skin areas will help to distinguish where fatty layers are more prominent under the skin.
Red-ish tones on the back and legs indicate where morbidity (Blood Pooling)will occur on a body lying prone.
GW Foundation Cardon Granite is a superb dull grey/green. It\'s entered as one of my most used colours, it\'s a good shade for alot of colours (I\'ve even used it to shade red).