The truth is, opiate receptors are a lot more binary in reality than this analog "theory" proffered by the purveyors of opioids. As with either substance, controlling the dosage obviously changes the level of effect on the recipient. In the U.K. they treated heroin addiction very similarly, with heroin. They'd give you enough to prevent withdrawal but not so much that you'd get high.

PS working the 12 Steps would likely help you with that self-righteous condescension issue that has survived your chemical addiction.