This is a great question and those regulations are only now being discussed. Many people believe that California will follow the model that Colorado used which is that medical dispensary and recreational are split. The medicinal requires a doctor’s rec to get access to product and the taxes are substantially lower than the recreational side which does not require a rec and has a different selection of products. The group CCIA, the California portion of the NCIA is working with regulators at the state level now to try to iron out proposals. Really, we will only know what the fall out will be from legalization, at a minimum, 9-12 months after the ballot passes.
Taxation is a tricky issue as taxes of course create revenue for the government but if they are too high, actually drive the black market. The sweet spot is said to be between 15%-20% and anything higher drives the price of the medicine too high and consumers seek alternate channels.
This represents my opinion based on my time within the industry. I hope this helps.