Having some issues with the hair, iv had to come up with a way around two main problems.
1: Intersecting layers at the root causing bad spec highlights
2: Hair looking flat, with hardly any strands visible.
3: Controlling Clumps
First issue was a very bad one, iv found that if I have less hairs, but use the clone to make the hairs up that spec issue is resolved.
Second issue was partly to issue 1, and not enough colour variations. Using the S,V variation, and tint colour in blend mode Darken, this brought out strands.
Third issue was solved buy duplication the hair tag, making a new selection set applied, and re root the guides, The style from the hair is kept, but is limited to the guides. I used Repell brush with Ctrl key to clump together, also use the clump setting foe the hair tag, not in the material. The last layer I added frizz.
Real hair has at least two colours to the spec, a light main spec, and a colour tinge, setting these up separately got me the look im after. Still got some work to do, but am getting there. Next is to apply this to a real hair style.