Thanks for the tips about Family Cycles. They are right down the road from an appointment of mine today, so we will swing by there.
Precision Tandems are off this week due to spring break,but they are running their March sales. We will try to check them out next week. I know their expertise will be very valuable. We had some college kid try to set up my wife and I on at 17"/15" setup, and we both require 21" min.