I now think I understand what you want to know. I think it is a matter of tension. You need to use a movable stop knot so the tension can be changed under way, or easily on shore. You just need to experiment to see what works best. There is probably no perfect tension that will work in all conditions so there will be times when you will have to simply pull the board up to where you want it. Try to get enough tension that it will hold it there most of the time. Too much tension will result in the board bouncing up while going upwind, which is harder to manually correct while hiking.