Pete,

Do you have an Ullman F16 sail by any chance.

If so then everything is in reverse.

That sail is actually too flat and has its leech fall away to quickly and too much.

So the old rule of thumb still applies, each sail is different.

And you say; if you stay up with the leaders then you are doing something right so remember the settings/what you've done for a later time.

Best of luck

Wouter