>but we can't expect everyone to keep up with it, possibly leading to lower participation over time
I don't think users choose to participate depending on how long the show is - rather, users choose to participate depending on what the show is, and whether their schedules allow for it. Obviously, it also depends on how many users are frequenting Heyuri as a whole

For teh Rozen Maiden stream (a well-loved, well-known, 1-cour length show), we had a max of 33 users and averaged 30-32 during the 1st half, around 25 during the 2nd half. I can't give exact numbers for previous streams since teh wiki is down, but I know that Rozen Maiden had a better turnout than many of the streams we've had this year (some of which were in the teens and low 20s IIRC)

That's why I say the run-time doesn't matter - users will participate if they're interested in the show and they're available, and since nominations are made and voted on by users, the show that users desire to watch the most is gonna be the one at the top