In order to be able to use Snapshots with any given parameter, you have to first assign that parameter to a controller. In your given situation you would do the following:
1) use 4-way knob to navigate and highlight the Input Block (make sure your Input it set for Multi or Variax)
2) press the Page Right Button to navigate to Input Block Page 2
3) make sure Preset Variax Tuning is set for: Custom
4) press Page Right Button again to navigate to Input Block Page 3 (this page displays the individual tuning for each Variax string)
5) press and hold Knob 1 (string 6), the display should show you: Parameter = String 6 and Controller = None
6) rotate Knob 2 all the way clockwise to assign Controller = Snapshots
7) now continue to rotate Knob 1 (Parameter) to select each individual Variax string and rotate Knob 2 (Controller) to assign it to Snapshots
Now you can setup each Snapshot for different Variax string tunings.
