This can be a real pain. Mike and Victoria are great figures but I never had such scaing problems with Mark and Posette. The only solution I've found is to use magnet deformers to bend the parts back where you want them not an easy solution, and not a pretty one, but the best I can offer. I usually do series(es) of morph targets for such specific bendies. I'm afraid I know nothing about joint parameters-- I'm still learning; that's just too complex for me!