Hi Simon

Never assume there is a "normal" case. You have to experiment with these kind of adjustments to see what happens - as you unintentionally did. Now you've learnt something to your advantage - thats great.

Every mast, sail and diamond setup is going to behave differently, so unfortunately you need to figure out what will make yours go.

You can start by looking at the sail on dry land as you gradually increase downhaul and mainsheet tension and swing the rotation lever around to see what effect it's having on the sail.

Lever pointing at the centreboards is certainly not a lot of rotation so don't be scared to try more (or less).