Looks interesting, the hairs could use some more polygons, though (upper left looks a bit polygonal to me). How many polygons are this, actually?

If using a lot of polygons in a small space, like here, do not forget to lower the shading rate for the object receiving shadows from your polygons (the head, in this case). This can reduce the heavy aliasing of the shadow on the forehead. Or try to use depth map shadows, which look better anyway for aliasing-heavy scenes, in my opinion at least, because of their built-in filtering. (Yes, i am aware that depth map shadows are not much liked, just worth a try if you cannot get your shadows dark enough :-)

How much time of the 3 hours did it spend in precalculating IDL, btw, is it worth it?