With a flatter main you're not maxing out cunningham as quickly. When you are maxed out you can keep it sheeted harder for longer before you have to start sheeting out and footing off to keep the boat rolling. Not talking about gusts here. I haven't felt short on power in lighter air either, but I do adjust diamond tension on the water if conditions change drastically.

Matt says you can get them result through spreader rake, and through diamond tension, and yes you can flatten the sail dramatically, (and if you go real crazy you can make the top really fall off), but I was really hunting for power when the wind lightened up with those settings. I think I took it to 42 on a black Loos gauge, and something like 2-1/4" of speaker rake. It was an obscene amount of prebend. Hindsight I don't think any of those numbers is safe for that mast, but it did survive.