Those who race with success all use loose rigs. If you grab the sidestay with your fist and twist it, you should see an angle of about 45-degrees. That is pretty loose, but could even be looser.

As soon as you go off the wind at all, the battens will bump up against the sidestay. With loose rigging, the sail will push the sidestay away and maintain its shape. If a tight rig, the batten will invert and you will have terrible shape.
Rick