This utility work great for G3 and G8 figures.  Be sure to  follow directions on how to import the figures after changing the rigging.  Save the import in a new folder and run the updater.  This works only for figures and not for props.

https://www.renderosity.com/forums/threads/2899983/genesis-3-poser-updater-free-utility-for-poser-11

https://www.renderosity.com/freestuff/items/76121/genesis-3-poser-updater