I'll try to get a shot Helmut...

Well, I tried the 61 material ferrites, and it lowered the SWR
significantly. No matter where/how the cable comes off, it appears to
work best right behind the feed point. Only one of the large 1" ones
seems to be needed. I tried adding more, but it didn't really make a
difference. It's still not perfect, but it's way better than it was
before.