its important to note that the further toward the base of the cactus, the more potent the plant is. my measurements are relevant to tip cuttings, for each foot under the top its about 30% more potent than the foot above if the plant hadnt been repeatedly cut at the same spot. by this i mean let 1 foot grow, chop it off, let another foot grow, chop it off. this would make the foot under this (and all other parts with age) MUCH STRONGER, the older the cactus is the stronger it is, typically 1 foot cuttings are a growing season old.