I’m thinking along the same lines, UPD. I’ve been hoping that it’s something like the 24 Hours of Booty, which our own Biped is participating in right now. Basically, they provide a closed course of several km and you ride as many or as few loops as you want. You aren’t expected to actually ride for 24 hours straight. You can take breaks, stop for meals, even go back to your room for a few hours of sleep. It’s a charity event and it’s about raising money, not seeing who can suffer the most.
My guess is that his legs burn out before the saddle even becomes an issue. That sure would’ve been true for me after just a few months of unicycling. I needed to stop and let my legs recover after riding for a mile or two, and I would’ve been done for the day after not too many efforts like that.
But then again, some folks are actual prodigies, and anyway it’s probably mainly about having a good time and helping out a good cause. A 29" with a road tire sounds like a good setup. I doubt a handlebar will matter much yet. Practice going up and down hills too, a lot!