Potential title: "The Custom Oil of Xam and Jenny." Maybe set in a village threatened by a blight. The villagers are desperate. The two come together, create the oil. First attempt has limited success. They realize a component was missing or a process was flawed. Update the formula, apply it widely, save the village.
Because of the "custom" nature, drain intervals are not one-size-fits-all. Based on the updated lab reports: xam+jenny+custom+oil+updated