my image above, which resulted in fine detail, deployed simply one group over the whole head. The setting was 35,000 hair strands with tip at .2 and root at .3 and took a few hours to render.

The hair was set invisible to raytrace. A shadowmap light with tight settings was on it, however.

If  the shot were closer, tip would have to go down to .1 or .15 as Carodan has stated.

the above image fails because of the issues at the scalp, but otherwise shows off wonderful rendering capability of PoserHair in my opinion.