I used 3dsmax2013 for rigging and skinning. Bone positions comes from the original face, I exported it with The Witcher 3D converter from JLouisB as he described it. I made every bone separate, Bone size is important, you must leave it as you created. Hierarchy not important, it comes from the skeleton used by redkit. Bone rotation is important, it was a real agony to find out. Maybe there is an other way and a skilled modder could find it out from the skeleton files but I'm not one. It would be a great help if somebody share this information. I saw the "farewell of the white wolf" interview, there you can see a moment where they skinning a head, so they sure have this information. I made so: weight entirely bottom part of the head to the neck, the upper part to the bone you work with and see how it looks, adjusting bone rotation. Bone sequence in 3dsmax is important, it must be the same as you can see it at the head in redkit.