Randy Dugan responded to Charles Andrews:
Not to hijack your shout-out to Charles, but I have an Eco-Duopar and a 14-34 Ultra 7, running 46/34 up front with a cheap KMS chain on a 1980 Schwinn Voyageur 11.8 city bike conversion. Works great range-wise, but it can be tough to shift just one cog at a time. This might have to do with the Sun tour ratchet stem shifters, which have a large drum. Haven't tried with any other shifters. +++++++++++++++++++++++++++++++++++++
Simplex "DeMultiplicators" are available from lots of folks, and help solve this problem. Basically, it is a lever that installs on the down-tube, and roughly doubles the amount of lever travel required for a given movement of the rear derailleur. I'm using one with a "Crane" RD and Shimano bar-ends, and it does help "unstack" the shift positions.
One is shown, top view, as eBay item 7180033273. More commonly, I've seen them without the plastic guide on the left side. You may have a bit of trouble fitting the cable that runs from the demultiplicator to the RD, it is a very small barrel head (as I recall it).