jeffd66939916,
Found it. You can get to the option directly from the Analytics report by clicking on the Experience Name under the field: "Control Experience" it will then bring up a pop-up where you can change it. See attached screen-shot below.
If this satisfies your query please like, mark as helpful and mark as answer. Otherwise lets keep the conversation going. Hope you have a wonderful day.
Screen-shot showing how to set the control experience in Analytics:
Mihnea Docea | Technical Support Consultant | Customer Experience | Adobe | (:: 1 (800) 497-0335