I’d play in this. I think two 90 minute sessions would be better than three 60 minute sessions. I don’t see any advantages of the latter, only disadvantages.

I don’t like the idea of the winner of each session getting an automatic bid. The person who wins the first session gets a 2-3 hour bye. You’ll get grumbling if the person who wins the last session would not have otherwise qualified. Why should they get in over people who played better across the whole event?

I think you’re overestimating the number of people who will show up after having missed an entire session or two. Their chance of advancing is like 2%. No need to cater to that. If hangovers are so prevalent that you’d build in accommodations to your format, just eliminate the first session so you can start 60 minutes later.

Also, using wins minus losses feels much more fair in this format. Otherwise it’s more about what games you get put on and hoping machines opponents don’t have long games.