dear mr. gthomas,
you intend to keep the center hull skimming, but the wind is going to allow that only when it feels the need to do so, which will most likely be rare indeed, unless it blows over 20 kts. all day every day where you race. Having a very long, open trunk adds lots of drag lots of the time and is an issue that needs to be addressed if you're serious about performance. If I had a choice I would absolutely have a dagger instead of a centerboard on my m23. Hitting rocks with a centerboard locked down is likely to be just as disastrous as it would be with a daggerboard.