In the end I did things a little differently than
@Rick Youngblood. I used 1/8-inch thick rubber gasket material from Ace Hardware to form a spacer by cutting the rubber in the shape of the wings, shortening the width to 3 inches to provide clearance for the ribs of the seat. I used two layers of rubber to form a 1/4-inch thick spacer. I attached the layers to each other and to the wings with double-sided carpet tape. I drilled new holes in the wings 2.5 inches on center and attached the front of the seat to the frame with M5 0.8 screws. Even with just a 1/4-inch spacer, the ribs clear the wings. I used Velcro to attach the seat to the frame at the other two points where it makes contact. See photos.
I took the bike out for an easy ride today. The Thor seat feels like a bucket seat in a sports car. At first the front end of the bike felt lighter and a bit twitchy. I think that is because the thoracic support of the Thor allowed my upper body to relax more and caused me to use a lighter touch on the bars with no pulling. That's exactly what I was aiming for. By the end of the ride it didn't feel twitchy any more. When riding hands-free I was able to apply pressure to the bike at my shoulder blades independent of the control from pedaling, which gave me more control of the bike. As a result, I set a personal distance record for hands-free riding. I was able to create good power uphill without pulling. I went up the final, short 15% grade to the house without pulling on the bars at all.