We used the Avocet inverted tread size 1.9 on our 26" tandem to do the one day Seattle to Portland (200 miles) in just over 10 hours. We spent a good portion of that day at the front of pacelines so I doubt there is very much penalty for going with a smaller 26" tire.
We've used it for touring and at tandem rally rides. Gravel and paved roads. Worked well.
I don't recall ever having a puncture with those tires and I don't believe they were the Kevlar belted either. Excellent high mileage durability.