At last: I made the final adjustment to the steering adjustment nut and now she is steering perfect; I can lift my hand from both handles at all speeds and she goes rock steady straight ahead. Even when reducing speed from 50 to 30 mph with no hands on the bars has no effect, no wobbles, no slapping, nothing. Cornering? piece of cake, she follows the line I want to go, falls in as I want her to fall in and levels out according to my wishes.
If I had known how great a difference a proper adjustment of the rear swing and the steering makes, I would have overcome my natural laziness and made the adjustments years ago.
Well, you live to learn.
greetings from a sunny and windy north