Hi

I can fly with both thumbs but normally fly pinching the right stick and my thumb on the left (mode 2).

If i fly inverted i remove my finger from the right stick leving my thumb below the stick as you normally have to hold some down elevator in the tension in the spring is enouph to move the ailerons and it isn't possible to pull the elevator stick back.

If i'm teaching somone i just tell them to use whatever method there happy with.

Simon