How do I use the Backspace/Insert when naming a preset on the G-Major?
This is how:
First press STORE once to get to the screen where you can change the name of the preset.
Then too use Backspace/Insert you need to first select one of the two arrow-symbols at the far side of the row of characters (fully counterclockwise).
And then, to actually remove/insert turn the outer parameterwheel.
Press STORE a second time.