How much pot?

Apparently people are having complicated and heated discussions regarding how much marijuana a medical marijuana patient should be allowed to possess.
I find it difficult to get very interested in that debate, although I understand that it’s important for the patients.
Here’s what I do think, however.

1. Law enforcement does not have a dog in this race. The patient can have a valid opinion. So can the doctor. But not the cop.
2. It seems to me that the amount that a patient is allowed to have should be at least the amount that the patient needs. Since that varies for each patient, there should be no set limit.
3. If you really have to set a limit, then I’d decide it based on safety and place it just under the amount that would cause a fatal overdose*. That way, you wouldn’t have to worry about anyone getting hurt.