Another option is to assign the aux switch to FLX. It works in either Play or Bank mode, and it targets one specific function. And that function will trigger a different type of variation for 9 out of the 10 algorithms (including Learn for either of the two Diatonic modes).
You can get unpredictable, but interesting results with a latching switch on LEARN (not recommended by Eventide). That's a little more useful for the Flex functions in other modes, though. MIDI triggering is another control option for Flex/Learn.
