I ran a 3 strike with 12 people with some custom rules, and it took 3 hours.
I gave everyone 3 cards to start. If you got last on the game you played you got to get another card. Other than that, we played pretty standard. My games don't play long, so that's wasn't an issue. Took time to get rounds going due to people not being familiar with the game, and also there were times that 4,5,6 people got into a back and forth playing lots of cards. Not sure if we did that right to be honest. Haha