Built up a new bike with a set of these. Not much more I can say about the Gravel King SK's that hasn't already been said before... If you like the 700c versions, the 650B is basically the same there is just more of it. I have a set of 700c x 35mm SK's on my other bike. Compared to them you get two more rows of small knobs (5 vs. 3), and an enormous tire profile.
I only have about 60 miles on them, but today I put them to the test in some nice gravel/sand/muddy conditions and they performed well. They easily set up tubeless, still playing around with tire pressures. Today I rode with 25 front and 28 back and could have lowered it a few more psi...
They are not light, both of mine weighed in at 573 grams a piece, well above the 540 gram advertised weight. But there is probably 20 grams of tiny rubber hairs that need to get worn off...