My intent would be to use Rene Herse 700c x 44mm (Snoqualmie Pass) tires on the Trek 920 and 650b x 48mm (Switchback Hill) on the Kona Sutra.
Thanks for any thoughts, opinions, advice, etc.
I agree that once you start riding wider tires, a tire in the 35 - 38mm range starts to seem a little narrow on gravel/broken pavement. I would go with the bike that allows for the widest tire. I am riding Rene Herse Rat Trap Pass (2.3") tires in a standard casing - with tubes. I've had one flat in about 1000 miles and riding them at 20/25 psi on gravel is very nice. Rene Herse now offers 'Endurance' and 'Endurance Plus' casings for more flat-resistance if needed. Running tubeless might also help with flats from smaller debris. I don't see the need for tubeless in my case.
As others have mentioned, the Kona Rove in one of its various iterations is a nice bike with the flexibility to set it up for various purposes. The Rove NRB is an aluminum frame with carbon fork that can take 650bx47 tires - $1799
