I wanted to share what David wrote in a recent email:
“The most important tuning point to pass on to people concerning the Panther is not to over-downhaul. People are conditioned to really crank the DH, especially when it gets windy. As you know I have gone away from this type of sail design because the excessive DH flattens the leading edge and makes the sails twitchy and unstable. Instead, the Panther relies on the outhaul for flattening. Flattening with outhaul is a more effective flattening method because it flattens the sail without flattening the luff. In order to have a sail (like the Panther) that flattens mainly with outhaul, there needs to be much more profile built into the front of the #3 and #4 battens. If you over-downhaul the panther, the shape at #3 and #4 gets pushed back and the sail get gutless and hard to handle.
Make sure you check out the outhaul and other videos at: http://www.ezzy.com/sails/panther09.php
Some people find it kind of tricky discerning the correct downhaul. You have to bounce the upper leech off the ground. Even at max downhaul, the leech still looks quite tight.
People are welcome to email me pictures of their sails rigged up at firstname.lastname@example.org“