Here's a still image of me just about to fix the back neck deformation on a rotate Z of 60 using driven keys on the joints translate X and Y channels and using a helper joint (the character is Barky. she is an original character design and model i made).
here's after about 30minutes trying to fix it
The idea is we get locator to move helper joint so we can zero out locator to get to default pose (the helper joint may have translates so cant easily zero out). Then we attach helper to skin and we drive the helper locator which in turn moves the helper skinned joint.
Another helpful thing is to use a skinned joint's rotation to drive its own translate channels. This was helpful as a starting point for the helper joints.
Hope this is helpful.
cheers,
-Nate
Inspired by
Rich Diamant's online discussion on using joint helper joints to correct deformation (rd3d.com)
