Welcome to the board bama. A crockpot will be fine but you may have to boil a bit longer if it doesn't have a higher setting. Don't know where you got your chacruna but it can be hit or miss UNLESS it's hawaiian from Maya Ethnobotanicals, then it would be much more potent than chacruna from somewhere else. Not sure why, I guess because the soil in hawaii is so superior, but it's probably about 4 times as potent as normal Peruvian chacruna. 12g would probably be plenty. Just want want you to be aware of that. 

Peaceful journeys.