The most I dealt with was around 36. I had around 28 chairs.
However, the feeder middle school had class sizes of 60+. There were literal riots, with multiple teachers injured, that the district covered up.
Stocks would absolutely not be allowed. I had a student that spent fifteen minutes screaming and cussing me out, straight to my face in front of a principle. When she said “I wish I wasn’t in your class” and I said “me too” - I got in trouble. (She was mad because I wrote her up for literally just walking into my classroom to sell snacks. She didn’t attend classes, she just did whatever she wanted.)