I managed to mount a Schwalbe 25-622 Marathon Plus tire, but it took a dozen zip ties to do it, and well over a dozen curses. If it ever has a flat, I won't be riding it home...
I do love the conclusion of the GP 5000 comparison:
"A bigger road bike tire (at least the Continental GP 4000 and GP 5000) provides a lower rolling resistance at the same air pressure. You do have to realize that at the same air pressure, a bigger tire will provide a less comfortable ride.
At the 15% tire drop air pressures, which are very close to the recommended air pressures for a given size, the tables are turned and a bigger road bike tire will have a higher rolling resistance. The higher rolling resistance of the bigger tire is because it provides more comfort at the 15% tire drop air pressure.
We feel the ultimate test is adjusting all tires to the same comfort level. When all tires are adjusted to the same comfort level, rolling resistance is nearly the same (0.2 watts max) for all sizes of the GP 5000."
I've always thought the "bigger tires are faster" line was B.S., and the graph at the same 'comfort level' is a straight line!