I have seen several recommendations for a straight fork for Sun EZ-1 bicycles, to eliminate the slow speed wobble. Also, shimming the seat up helped. Combining the two, would putting a 20 inch straight front fork and 20 inch wheel help both conditions? The frame would look a little odd, with the front up 4 inches higher. But the Bachetta have a sloping frame tube anyway. And the seat would slope a little more.
And I got clipless shoes, finally. I did not have problems tonight like I did with the road bike in 2001.