“How much propofol do you need for conscious sedation?”

Enough to knock you unconscious if needed.

There is no way to answer this simply, and it appears from the question that a simple answer is what is being sought. The amount needed will vary from one individual to the next. Yes, the amount of drug administered per Kg of body weight is a good starting point to accomplish sedation, but in addition to considering body weight, different individuals have a different tolerance (or sensitivity) to propofol or any other anesthetic agent. The amount of a drug needed to accomplish sedation will also depend on the intensity of the stimulus for which the sedation is provided. A minimally painful stimulus will require less drug to achieve sedation, but a greater, more intense, stimulus will require a larger amount. This is part of the reason why there is a well trained individual, either a Nurse Anesthetist or a Physician Anesthesiologist (possibly with the assistance of a certified Anesthesiology Assistant) continually monitoring the patient, and adjusting the amount of anesthesia (whether it is propofol or some other anesthetic agent) throughout any procedure for which medications are administered for sedation.

Most dosing of medication is based on weight. Propofol, being a drug with a short half life, is often dosed by infusion at a specific rate and titrated for clinical effect. The total amount would vary by the size of the patient and the type and length of the surgery or procedure