Well... went back to the drawing board or rather, the bike shop and seem to have rectified the issues I was having that were all about the derailer.

The new dual drive is using a Suntour Honour derailer and a somewhat modified hanger to compensate for the upward sloping dropouts on my Twenty. I'm still using the back to back 3/32 Shimano cogs and 3/32 chain.

The test rides were perfect and the ride home was excellent... 6 nicely spaced gears and the shifts between high and low were like buttah.