I have been down this path with my 323 Libations Too. This is a very good discussion topic and I'll add my perspective:
1. I grew up sailing othe Great Lakes and would not spend the money on this mod just for Great Lakes sailing. As I recall, most high wind events are associated with Thunder storms and a safe and convenient way of handling such conditions is to drop sail and motor through the storm....my opinion only.
2. I considered a cutter mod for Libations Too but the 323 does not offer a good structural connection for the stay aft of the anchor well. The obvious alternative was something forward of the anchor well, which led me to the addition of a removable Solent stay. My thoughts on this matter and my final installation are presented here:
http://rollinscs.com/boatpages/projects3page.htm 3. When considering a storm sail I opted for a smaller sail than may normally be considered appropriate for the 323. Part of my reasoning was that my 95% jib, when furled to the end of it's reef patches, is about the size of a standard storm jib for the 323. For this reason I selected a smaller storm jib both to better compliment my existing sail inventory and to make sail handling that much easier.
4. I have never flown my storm sail in real storm conditions, but I have used the Solent stay for a second jib (twins) on coastal cruises down wind....and it works great. I have also used the Solent stay to hoist a second jib, which in turn allows me to change my roller furling jib without a complete stop. This may sound a bit ridiculous in a boat designed mostly for cruising, but the stability of the boat while in motion (as opposed to bobbing in the chop) and the ability of the staysail to help keep the roller furling jib on deck while lowering it were greatly appreciated.
5. My last comment, also without any mathematical back-up, pertains to the center of effort discussion. While it makes sense that the ideal shortened rig should not alter the overall center of effort, the real world is somewhat different. On the 323 I have found that she sails best on her feet and that reducing sail to reduce heel should be the first priority when encountering higher wind speeds. I have sailed along at over 7 knots with no head sail and my main reefed to it's third reef point. We were reaching at the time so center of effort was not an over-riding issue...but it was clear to me that any more sail than the third reef would have added little in terms of boat speed and would have added much in terms of stress on the boat and crew.
Hope this adds to the discussion....