Cruising, Racing, or Both?
If you are racing, the rules seem to favor the largest possible genoa-type headsail. That would be a 155 deck sweeper. Most sailmakers talk about reasonable shape with a 20% reef, so that would get you down to a 120 at the maximum reef of the 155.120 is too much for a good blow on most boats. (I'm thinking 18-20 knots.) So you'd need a 110 or 100 for days with the higher winds. (My h27 came with 110, and 135 headsails.)If you are a cruiser, then consider an Asymetrical Cruising Spinnaker. In light winds it gives me a lot more sail than a 155, and I get get to a close reach which is about as close hauled as I cruise anyway with my shoal draft keel. In medium winds the reaching is fantastic, and it's almost as good as a full spinnaker (but much easier to carry - no pole or guys are required) on a run. Then I have the furling 110 for working close to the wind, or for the heavier weather. The spinnaker douses in a sock in a few minutes, so switching between the two sails is take the Admiral and me less than 5 minutes without pushing.The Asymmetric is not easy to tack or gybe, though. You have to douse it in the sock, and then carry the sock and the sheet around the headstay to deploy it on the other tack. For cruising Lake Erie, or another large body of water though, we just don't tack of gybe much.My last (and best) thought is to find a sailmaker who will think this through with you, and come out to see your boat and current sails. This is a free service of a good sailmaker, and let's you build a relationship with one before committing to anything. I priced 4 lofts, and talked with the sailmaker in each one before working with Greg Kotko of the Doyle Loft here in Cleveland, and I'm very happy with the result for Lady Lillie. I'm certain that finding a good sailmaker you can work with is much more important than the brand name.