Around here in the spring we often get 70 degree winds over 40 degree water. The sun and geography try to mix these winds down to the surface but rarely does. Last week I was lit on my 8.9 Hydro, while a friend was windsurfing with 9.0 on a Bic Techno. The farther upwind (away from warm land) I went the more the wind mixed down to the surface. You have to be carefull launching a big kite in these conditions. I had to chase after and grab a lofting friend last year after he put up a 9.0 f-one foil in (apparently light) onshore winds (with many unsuspecting people down wind a row of parked cars, a bunch or Hobie cats and finally a harbor full of sailboats) Finally, we decided the only thing to do was to let go of the kite. F-one foils have a habit of remaining powered beyond the end of the safety leash, it broke, the kite bar cleared the people's heads sitting at picnic tables by about 1 foot it continued on through the Hobies and cars all the way to the harbor, I ran after it and found it sitting dry on one of the docks with the lines trailing off behind with out a tangle.
So I think the extra line length can make a huge difference depending on how far up that wind is. Just plan ahead.....
Lane

Thanks Lane,
I will definitely give a try to lengthen lines in underpowered conditions.
I spoke to some experienced motodeltaplaning guy and he confirmed that wind 100m above the sea surface can be much stronger than on the ground.
He admitted that hope not to meet me up there