Hi BelSkorpio & Jan,
I have only used the combo a few times and agree with Jan that from 17 knots the draft starts to wander. This is on a day when it starts out light and you tune accordingly. You might get more top end range with tuning but I would rather go to the 7.8 and 68cm board.
I am 110kg/193cm and find that the 130L/84cm(similar to the 131, a little longer@ 241) is just under what would be optimum for me to plane earlier on really marginal days. I hope the extra volume & width will sit a little higher and not be as physical to get planing. I am sure it will lose slightly to a lightwind slalom at the top end deep of the wind but I am after a board that is always on the plane and has the best average speed. I heard from the dealer conference that it is a really fun board to sail.
I agree the MkIII is harder to trim - if you try to your old favourite rigging tricks, I am still learning to re-think my trimming to suit the new designs.