A single aux switch would be sufficient to use 2 presets in a song with a single click (no dancing) if Eventide could implement a preset toggle for the aux switch.
1. Activate a preset.
2. Queue a second preset (not necessarily an adjacent preset).
3. Switch between the two with a single aux switch.
Unless I a missing something this is a much simpler method to use two presets on a H9 than the current up/down technique.