There is a lot written about GARBO, one of the most successful and prolific double-cross agents used. Much of his good work only worked because, like most agent handlers in Germany, they didn't want to believe they could make a mistake and have been so gullible, and so continuously pushed through reports that, with hindsight, were unbelivable.
For balls, I think GARBO and ZIGZAG are on a par

, both pushed for their jobs and both, initially, not wanted by the XX-committee.
Thanks for highlighting this, it's good to see a piece of their actual work