I'm in the process of that myself. The hair meshes are found in characters\models\geralt\coif\model folder once you Uncook the files.
There's some terminology i'm having a hard time with, and i wonder if anyone can help me (i wanted to make a thread asking about it, but i'm new).
There are three seemingly identical meshes for the same piece of hair, with just slightly different size (in the 100KB range, thereabouts) and just ending in a different suffix. As in "c_02_mg__halftail_long", then "c_02_mg__halftail_long_br" and "c_02_mg__halftail_long_inq", with no discernible difference otherwise.
There's also a variant on the prefix, where one will be "c_02_mg__halftail_long", and a little ways down the list there will be c_02a_mg__halftail_long, with the difference being the hair mesh being slightly weighted down in it's pose (maybe when the hair is wet?).
Not all hair sets seem to have all of these variations, but enough of them do that i need an understanding of what they're for. Is anyone able to help?
EDIT: I understand the _br and _inq suffixes seem to be different instances of it being tucked, though i'm not sure i understand the difference beyond perhaps different types of armor. Still no idea as to where the prefixes apply, though.