I didn't like the 1090 on the tandem either.
but I do like the XX!
The jumps on the 10-spd 11-32 don't bother us at all really.
We tried the 11-28 (with a 28t inner ring), and found that we ended up shifting 2 gears at a time, many of the times, as the momentum swings on the tandem are so big. With the 11-28, we ended up shifting a lot... especially on Mt. Tam double.... those damn rollers had me shifting like crazy. We still shift a lot with the 11-32, but a little bit less.
Also, I like having the 11 & 32 cogs for use with the middle ring, so I can keep the front on the middle ring for rolling terrain, and still have significant range.
How was climbing Pierce and Eden? Did you guys do it seated/standing? How was your gearing/cadence? More importantly, what did your stoker think about hitting some steeper climbs?