I was able to run a second time with one of my players, who turned his level 0 jeweler into a cultist. He rolled up rope work, patron bond/invoke patron, spider climb, and ward portal. The mercurial magic was really fun: his rope work turned out to be a psychic focus, so he cast that before some of the other spells even when he didn't really need the rope. He decided to patron bond with Aza Dahaka, which gave me a good chance to try and come up with invoke patron results on the fly. I used the existing table for Bobugbubilz and reskinned the results to be desert wind focused. That worked okay, but I think some guidelines for building invoke patron tables would be helpful, as would some guidelines/ideas/tables for favors requested. My read on invoke patron was that the favor wasn't necessarily called in right away, so you almost need a patron record sheet to keep track of the strength of the current bond, invoke results, favors owed, etc.
He also did spellburn a few times, which he appropriately described as coughing up blood. The first time it was with rope work, to try to entangle the bear. Entangling is a pretty high result (18), so he didn't manage that, but I let him shape it into a knot around the bear that he could physically pull taut once it finished coming into shape. His second spellburn was with invoke patron, and worked well, giving him a 20. For Bobugbubilz that summoned a devil toad, so we had a whirlwind appear that followed him around for an hour. The table gave no indication of the strength of such a summoning, but looking at the previous tier of results I saw that it had a 2D6 entry. I gave the whirlwind +3 atk 2D6 dmg, which might have been a little strong, but I'm not sure. The coolest result of that was when he opened a door on a room of kobolds, sent in the whirlwind, and warded the door. We just rolled to see how long it took all ten of them to die. The tone of that felt spot on for a cultist, with his mute hireling just holding the torch as they looked in on the slaughter.