Wouter,

One could say that the jib works in the mainsail's updraft and the mainsail in the jib's downdraft, but I miss the advantage of the combination.

If I look at the jib, it can be set in a more opened angle due to the main, but if I look at the mainsail, it needs to be moved closer to the centerline with a jib, compared to without it. Doesn't seem to work this way.

Luiz