For some background, I used to ride my 1983 road bike everywhere back in the 80s, raced club criteriums and TTs too. Sew-ups and clinchers, usually 21-23c, 90-110psi.
After 30 years, I bought a 27.5+ hardtail mountain bike. Fun, but i missed the "road mileage." The gravel bike thing caught my attention and my Norco Search XR 105 came with Clement 700c MSO XPlor tires in the 40c size. I was fast enough on pavement, and anything i may have experienced, i chalked it up to age and being off a bike for 30-something years. I really liked the Clement XPlors, but I wanted 650b wheels!
Over the past few weeks I've been riding the 650b Teravail Cannonballs in the same areas I rode the Clements, about 60/40 pavement/dirt. I think the tread pattern is somewhat similar between the two gravel tires. Of course the Cannonballs are bigger. I'm running them at the same PSI 40f/38r and tubeless as I did the Clements, and i notice no reduction in speed on pavement. I doubt I could hang with a local roadie pack of course, but that would be mostly due to my fitness.
One nice advantage is I find myself cruising through brief soft sandy stretches with more confidence than I did the Clements. Plus I love the skinwall color. The tires are mounted to Kinlin TL-23 asymmetrical rims with Bitex hubs built by Mill City Cycle and measure out to 47 or 48c, i forget right now.
eric/fresno, ca.