Are you planning to leave these boats rigged on the water? Do you really ALWAYS plan to have more than 3 people? I am thinking that an Hobie 18 would be far easier to launch and rig meaning you will sail it more and divide trips for that many people up instead of several big trips. I like the idea of the 21 or 27 but rigging them sounds like a PITA and I know that would push me to not launch it for those shorter days.