My North Ltd has the two rear straps configuration. What or when would you use each stance? Outboard for a upwind or crosswind reach? Inboard for off the wind?
Yes they are for when the wind is 25+ knots and you want to get downwind in one piece. Surprisingly the easiest way is to constantly loop the kite with your back foot in the middle strap.
they are known as the chicken strap/straps. Lots of peole dont have them on their boards, they only go on when its really windy. They are handy when you are learning as the board is a lot more controlable downwind in the back strap although you will be slightly slower
The inboard straps (on other brands there is just a single middle strap) are referred to as the 'chicken strap'. This is when you feel out of control downwind and chicken out. So try to stay in the outside straps upwind and down wind :) It's a handful in the wind. As Alty alluded to when going downwind when it is windy it can be easier to go lower, or more with the wind, and do more kite movements such as looping.