Yes, I’d gotten confirmation that off-label SRAM11-36 worked for others, so that’s what I was thinking. 11-40 would be even better if the “mid” ultegra derailleurs can handle it.
I’m that person! I grew up on ~2cm of rubber width at definitely no less than 110 psi, or else you would surely get a pinch flat and not be able to keep up with the pack!
But then, not even 5 years ago, my first Tri bike arrives with fatty 25s. And it still moves at a clip. Imagine. Then I spring for this OPEN bike to replace my old road bike, and I spec’d it with 700x28 tires, tubeless, actual width is ~31mm and close to 105 rule. Follow recommended PSI, even though it’s only 50% what I’d usually run. Holy CRAP, I could butter bread biking on chipseal. If crotches could sing, mine would go straight to Handel’s Messiah. They don’t tell you when you start off that PSI stands for Pubic Sledgehammer Impact. So I go back to the tri bike and squeeze in 28s tubeless, which just makes it under the line with my weight/bike clearances. Check. These days, while some folks here are posting on the bane of tubeless, I’m out enjoying my long rides. So, yes, I am one of your converts.
I created a ‘road’ bike from a chinese mtb frame and a cyclocross fork to climb the high mountains in California (especially Owens Valley) because the high altitude roads were horrid, but the riding was great. For big, ballon-y tires I’ve used old Schwalbe G-Ones Speeds (when they were still fast), Furious Freds and Conti Speedking Racesport tires for tires in the 45-55mm range. They were amazing on those roads and still fast as road tires (probably faster on some of the rougher roads). Now that I’m in Utah, I went back to my old road bike (38 front, 27 rear max) because the roads are so much better, but also because two of those tires were discontinued and one is now using a really slow rubber compound.
I would try 650b wheels with Thunder Burts at 2.1. They are faster than most gravel tires and my front TB has lasted forever and is really solid tubeless. My ‘gravel’ bike is actually a dual-sus mtb mongrel with 27.5 TB up front and a smoothed-out Raceking Protection on the back. A bit slower on pavement, but amazing on gravel.