Headsail Shapes
The original poster said he wasn't interested in racing, so the relative diference in performance, particularly with a roller furling sail probably isn't measureable.IF you were interested in racing, particularly in a One Design fleet, there would still be diferences in the possible cut of the headsails (high clew, deck sweeper, etc)from various sailmakers and that could be measurable in a race.Your question about the shape of the headsail tack area where it goes out over the life lines has been addressed in some older boats by taking the life line off the pulpit and fastening it down to the deck, thus creating a 'slot' where the luff of the sail is not hampered by the lifelines or bow pulpit. I don't know if that would work on a 23.5 or evan mean anything in speed.If you were interested in racing, and getting the best sails to do so, I'd get the max sized Mylar /Dacron laminate Genoa in a deck sweeper racing cut on a 'Tuff Luff' headfoil, and get a loose footed racing cut mainsail with full top batten and the remaing battens in IOR length and maximum roach. You would first want to max out the boat's potential As Soling 42 said, possibly an upgraded traveler , cunningham, boom vang, backstay adjuster, etc and most certainly a smooth faired in and wetsanded racing bottom / keel finish.Despite all that, the shape of the sail on the boat in the picture seems fine for cruising, for good visability and for less wear & tear on the pulpit and life lines.