If you could only buy one book on SOF kayak building, which one would it be?
There are a few more books available than those you mentioned ... like Bill, I have several ... but if I had just one it would be Cunningham ... because the process is clearly and thoroughly explained, there's lots of pics and I can find stuff easier than in other books. All the other books are fine too ... but I just relate better to Cunningham's approach.
Also have a look at Wolfgang Brink's Instructables ... his approach is direct and easy to understand. I paddle with guys that have built 'em ... they come out just fine and have a nice sexy shear line.
And then there's SOF build logs on the net ... some quite extensive ... always nice to see how other people do it.