I have edited a short video of the best footage of sea kayak sailing: http://youtu.be/P21uMgpWs3g
I have been sea kayak sailing for 10 years and the last 4 with Flat Earth Sails.
I find the simplicity and reliability of Flat Earth sails suit my needs for sailing with kayaks that are rudderless ( I used to sail with rudder kayaks too but now prefer skeg kayaks).
My favorite sail for winds above 15 knots is the 0.8 m² while the larger 1.0m² is slightly faster only with lighter breezes.
I no longer dread windy days and actually prefer a bit of a breeze since with Flat Earth sails I can sail out and back (wind on the beam, from the side) and not need to paddle at all, if I don't want to.
On longer trips I find that the sail alleviates fatigue and I can paddle greater distances.