As I recall, Karl had a couple of the old "Big Bertha" slot machines, and they were indeed set for 60% payoff (1970's) - and he used those as a trade with cash for a couple new Bally $1 slots that he had set at 90%. When they were successful, he went back to order two more machines but, he saw something new that caught his eye.

Karl was introduced to Bally's new "carousel" of slots idea, and thought instead of having them in nickles, he would have a similar set-up at the Silver Club in dollar slots - and set at 95%.

The following weekend they were installed and proved to be quite successful. The "dollar-slot carousel" was born, and it wasn't until several years later that the big clubs in Vegas began converting their lower-denomination slot carousels to dollars.

Karl should get credit adapting Bally's new innovation.