I just got an email reply from John at CLC who pretty much agreed with everything you said. They're a great way to make a kayak sail, but really never going to be a great sail boat.
Those look like fun, but I'm sure I couldn't move one around with my little scion. the need to be cartopable or towable by a car with a towing capacity of "0" is a real problem when it comes to vessels looking to cross the channel.
I guess that was my question, why not just used a square headed full batten sail instead of a gaff or lug sail? is it just the cost or difficulty of making that type of sail? It seems like it would do everything the gaff would, including the low mast and large sail area? I'm sorry if I'm missing something obvious here.
Thanks again guys, this is proving to be quite an educational experience.