Well, the adventure continues. I removed the 130mm stem and 4" Delta stem extender. They made the steering slower and the bike feel "wallowy." I also couldn't get past how disproportionate it made the bike look.
So off with them and it's back to the Cannondale stem set, 100mm 10 degrees...
and on with a Selle Anatomica NSX saddle. This is the no-keyhole model that is similar to a Brooks. The "X" part used to be called Clydesdale (!) as it is for heavier riders. The X models have two bias plies- angle-cut leather layers - heat-bonded to the bottom of the top cover. It's a slightly different theory than a Brooks.
The important thing is that it has the rails toward the front, effectively giving the saddle MUCH more setback than my Fizik or a B17 that I used to have.
Rolling off the sit bones forward to spread the weight out onto the rami feels odd. It's not entirely pleasant, but if I get used to it, the saddle will take the shape.
SA advises setting the saddle up slightly nose high to start, to prevent the sensation of sliding forward. I don't know if I'm going to love this saddle, but it certainly provides a good inch more setback than the Fizik.