that's a good link. Actually my problem is not how the best trim would look like in theory, but how can I close my leech in reality.
For strong wind my sail looks like I wish. In light winds I couldn't close my leech as much as I wished (with tight main sheet and open downhaul). Maybe my wish of a closed leech is not realistic at all, but with your suggestions it could be that the battens in the top are too stiff or I still have too much pre-bend or the sail cut is not ok. Hopefully I will have better wind next week end, so I can figure it out and make some more pictures. So far thanks for your comments.

Cheers,

Klaus