Timbo, if it is just you and your wife, and you are just talking about one overnight at a time on the boat, and you are only going to race a couple times a year, I would go for the 24.

It's not just a matter of the 28R costing double, every component on the boat probably costs at least double to replace. EVERYTHING is bigger and more expensive, from the lines and blocks to the anchor.

From a woman's perspective, I have never seen a Corsair trimaran of any size that I would consider habitable for more than overnight. So you might as well go for smaller and less expensive.