Aloha Dave!
I have made tons of coconut oil for use in cookies and other yummy vegan baked goods...
I used 1 jar (about 12oz) of organic coco oil, and (literally) about 2 handfuls of
trim, simmer on very low on a stove for about 2 hours. The cookies I made were quite potent little ginger snaps and one could really only eat half...
I would think that Buds would be more potent so you might use less. And also, coconut oil can burn quickly and easily. I have heard that you can certainly overcook the weed and end up with nada... I would imagine that 12 hours in a crock pot would be cool as long as the heat was very low.
I have burned it before as well and caught it quickly, the oil was still good but didnt have the best of yummy flavors :(
Anyway... these are my thoughts and experiences, I would love to hear how your trials go
Aloha!