I just use the dials if any are available to get  hair in a reasonable position and then fix it in post work in a graphic program. 

After I do my full render I  usually end up doing 2 area renders. 1 render with the body part invisible and I render the hair area.  A second render with the hair invisible and render that body area.  Then in post work I overlay the body part and the hair part and decide which looks best and then clone what I need.  Tedious? Yes! But still easier than trying to work with magnets, which are my bane. I've never been able to get a magnet to work properly, at least in order to be able to move just the part I want instead of the whole thing.  

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi