The problem with tweaking the rigging of the character p4 woman is if
you change the joints you will have to change all clothes as well because
the joints and bone rigging is the same and will cause the clothes to
conform in a way that you can't use in poses. It is the problem with any character
who does there own rigging.
So you would have to tweak the mesh itself.
Oh! very nice Andreas! She is a beauty and this would make a lot of people that use other models heads turn and mouths drop.