Masthand as far to the mast as possible. Makes shifting easier. Sailhand a little wider out too. Gives more control.

Depends on the jibe you’re after. Leave front hand in sailing position, but slide back hand further to depower (laying rig more parallel to the water).

For example, if you are walking on the right tack (the right hand is closer to the mast), then during the turn you slightly bring your left hand closer to the clew corner and put the clew corner out of the axis of the board and then the legs go into game: the front leg remains in loops, but at the same time you start to put pressure on your fingers and move your hind leg behind the axis of the board (on the opposite side) and press when the board has turned, toss the sail and pumping to speed.

If you do a non planing jibe the hands can definitely slide backwards quite a bit (especially in light winds) in order to turn around more quickly. Just be aware that for the sail shift your mast hand needs to be as close to the mast as possible and the mast needs to be straight over the board, so that the force created through the sail is controllable. So yes, feel free to move the hands a bit, just remember to move them back before shifting!