I have built two Guillemots, one 17ft as per Nick's plans and one 15ft 6" with the same x-sections but with reduced station lengths.
I am 5ft 11" with size 11(UK) shoes and weigh about 186lb. I find both boats fine to use. The 17ft version has a little better glide.
Both are fitted with small keel skeg keels which terminate about 3ft behind the cockpit and have a max. depth of about 1 1/2".
I made them deeper and then planed them down after paddling trials. They wagged their tails a little without.
(Bill Hamm will now post about my bad paddling technique!)
This gives just enough tracking to suit me and my needs. (Everyone will have their own ideal) The boats tend to be used mainly
on slow flowing rivers, with the occaisonal sea trip.
I'm sure all the other boats mentioned in this thread will do just as well, but for my money, Buy Kick's book and go for it!!

Regards Les Cheeseman