The Gravel King in 700c and 650b are very different tires. I did a couple thousand miles on both. The 700cx38 is a reasonably supple tire but nothing too exceptional, it rolls ok. The profile is weird, it's a wide tire but it's short, I also think the published weight is wrong but will need to check my measurement to confirm, true weight is closer to 400g which is done by keeping the tire short. The Barlow Pass is, oddly for Compass, a true to size tire which explains part of the weight difference.

The 650bx48 is very stiff and rolls significantly worse than Switchback Hill or even the WTB Horizon. The difference between 650bx48 and 700cx38 is much larger than one would suspect just looking at the data. The wider tire rolls slower, especially above 25ish miles an hour, this may seem silly but all the descents I do I end up anywhere from a few dozen feet to a hundred feet shorter up the next hill on wider tires. This adds up, especially on longer rides. They feel less responsive but give much more comfort on rough roads/gravel. They also seem to hold their speed worse than the larger wheel. I currently ride 650bx47/42 because I like low trail, if I were riding a regular mid-trail or high-trail bike mostly on pavement I would be back on 700cx38. Mostly gravel? 650bx48 but not gravel kings.

I pick my tires 1) how well does it roll 2) riding surface. I regularly ride four different bikes with three different wheel sizes.

Overall the Gravel King tires are much less supple than the Compass offerings, which makes sense as they are much cheaper and do not use the same casing as Compass tires.

Tubeless tires are all about the bead. IMO Compass specified a bead that would work ok for tubeless but would also allow most users mounting the tires on old box section rims with thick velox tape to get the tires on using their hands or normal tire levers. This hedge has led to a lot of issues for both user types. I think the company should have created a line of tubeless tires using a much tighter tubeless specific bead like Panaracer's road tubeless bead and then kept their non-tubeless options as completely different tires.

The issues with Compass blow-off stories are due to the fact that blow-off pressure is achieved at 1.2 times max pressure rating. This safety window is much lower than it should be. I'd never mount current Compass TC tires on the front of a bike and only hesitantly run them on the rear.