As to the gearing for climbing, there are undoubtedly others here who can chime in.

But the climb that got us on Saturday was up around the 15-18% mark. As Machka says, up to around 10% for relatively short distances, we have been reasonably OK.

At the checkpoint where we pulled out of the ride, another rider took great interest in the Santana. He owns a tandem of Italian heritage. We got to discussing gearing for climbs. He figured a 24 or 26T chainring might be a solution with the 32T cog on the rear. I do already have a 26T 5-bolt ring, so I might give it a try. But I also am thinking of leaving the 30T on there and trying a cassette with the big 36T cog on it.

I have to sit down and do the calcs on the gear ratios just to see what I really am dealing with and what the realistic possibilities are.

I figure that I can keep the bike reasonably straight and upright at around 4.5km/h or a smidge under 3mph. When on the tandem, Machka and I have a reasonable cadence, but she doesn't particularly like mashing, so keeping a moderate cadence with a quite low gear-inch at 3mph is feasible.

Now, where's that calculator.