Here is another example using one of the P6 James strand hair resized to fit M4. I doubled the number of hair as we could see his head through it.
The same render settings except that i lowered the IDL bounces to 3. Render time: 15min 20s.
I noticed the render is faster if you make the skullcap invisible :)
To adapt hair from other figures, you need to translate and scale the skullcap to your need.
My Store