PERFORMANCE OR COMFORT???
I am more interested in performance than in comfort! If comfort is your goal than the Schwalbe one tires are probably not the best tire to be using. They advertise them as fast and puncture resistant.
However our Calfee Tetra with 23/25 tires is very comfortable for us! But I announce bumps for my stoker and she is able to adjust so that bumps are not an issue.
if comfort is the goal then I agree big fat tires and maybe even front and rear suspension should be considered. Maybe Calfee will adapt their Manta (sp) suspension for use on a tandem.
on our 36 degree 15 mile ride today we both noticed again how smooth the bike is with the Schwalbe One tires.
We are senior citizens but we still enjoy a spirited ride. We own several Strava segments in our area. At times we poddle along but when we feel like we like to be able to hammer! That narrows my choice of tires/wheels, I do not want 28, 32 or 40mm tires on our tandem, maybe when we are old I might change my mind. Our current age is 70 and 71 years young!
Ritterview rides a super nice, super light Calfee Dragonfly. I think that this is a very stiff bike, from what I have read it sounds like the stoker is not happy with the ride. Thus the big tires, suspension seatpost etc. If I remember correctly the stoker stem was made longer which might have moved the stoker into a position that placed more weight on the seat. Maybe going back to a shorter stem might help transfer some weight off of the seat?