That's kind of funny, for me personally I never use Stone Fist because I don't like to calculate regen fighting from knocking my enemies through walls. For a "character" boon I would rather use Stone Form although -resist boon gets bigger priority.
Stone Soup REALLY needs to become 1 per shot like Enlightenment. You lose too much popcorn EXP otherwise.
Stone Skin... well, the boon it replaced, the "First Strike" boon... that one was really cheap piety wise which made it usable for killing normals. Stone Skin though, you'll usually be running with full 65% from building up the Binlor piety anyway. It's too expensive to use to kill normals and it's also way too expensive if you're fighting a long sustained boss like Frank/Super MM. It would be useful on a theorotical glass cannon physical boss but most of the glass cannons like Aequitas tend to be magical. Bleaty is a physical glass cannon but he deals WAY too much damage for even 65% physical resist to survive.