My usual take on cannabis taxes: tax low at first, tax by weight or THC, be careful about exempting medical. Government sales are better. After one of my co-panelists enthuses about female and minority MARIJUANA MILLIONAIRES, I show nervousness — I don’t think there will be very many. Connecticut Legislative Commission on Women, Children and Seniors Cannabis Forum, Legislative Office Building, Hartford, Cannabis Revenue Panel, April 30, 2018. Video at http://ct-n.com/ctnplayer.asp?odID=15247; my intro at 39’30”; main remarks at 2’34”.
I agree with my new friend Morgan Scarboro of the Tax Foundation more than I expected to, since I’ve been plenty critical of the Tax Foundation on this website.
The Center for New Revenue 
The proposal to allow the vendor to declare strength caused me to recall the humorous (only to a tax specialist) old Connecticut “income tax” on the income of attorneys. That law imposed a progressively rising flat fee on attorneys based on their self declared degree of success. I often wondered how successful the tax was with raising revenue. Did ego or greed drive the law to produce more or less revenue than an accurate measure of the status of the Bar would dictate?
From https://www.huffingtonpost.com/pat-oglesby/taxes-cannabis-gulliver-j_b_7761696.html
When it came to “Ways and Means of raising Money,” in Part 3 of Gulliver’s Travels, Jonathan Swift
. . .
Meanwhile, for other behavior, Swift had another professor, with a completely different method of assessing tax due: Instead of juries, let the taxpayer himself assess tax, on the honor system. Here’s one example: the “highest Tax was upon Men who are the greatest Favourites of the other Sex, and the Assessments, according to the Number and Nature of the Favours they have received; for which, they are allowed to be their own Vouchers.” Decode the olde English, and you’ve got a tax on either promiscuity or boastful lies about sex — a “Swaggering Stud” tax.
OK, if you want serious tax design, Gulliver’s Travels won’t get you far. You might try State Tax Notes, or High Tax States, or RAND’s Vermont Insights instead. But if you think something is a Vice, taxing it won’t eliminate it. Not only do taxes miss targets you want to hit, they hit targets you want to miss. The real world is messier and trickier than fiction.