I went full wimp to 26T paired with 10-42 on a 650b. And so far on the Shore and in Squamish I've found it to be a pretty great set-up. My thought process was this (and I present this in the spirit of The Dude and not as the Only Truth):
1. While I could pedal my original 30T, there were a few very steep climbs or times when I was very fatigued that I really wanted lower.
2. I didn't love the gap from the 42T cog to the 36T cog. Not terrible but less than awesome.
3. By going to a 26T, my "normal" steep climbing gear is 26-36 and the next cog is 32T, which is a bit better spacing. 42T is a true bail out gear and is rarely used (but is fantastic when I need it)
4. Top end of the 26-10 is 34km/h at 100rpm (650b). That never seems to be a problem on trail (if Gwin can win chainless, I probably can find more speed with better technique vs. pedalling). And 34km/h on knobbies seems pretty good on the road to me. Plus I can spin my road bike pedals at 110rpm… I probably have a few more km/h if I want them.
5. My chainline is better since I spend more time in the middle of the cassette. And wear on these 1x systems does seem to be an issue so I think that's a good thing.