Check out Tom Yosts page. He might have something along that size already. You can always change the size of his yaks slightly. Making your own Yost offsets for such a small kayak is a pain, unless you undertand computer modeling. Aaron seems to undertand the process pretty well. I built his recovery and gave it away when I moved 10 states away. It definatly involved a lot of fudging.
Aaron... Sweet yak. I noticed the material, did you get it from an industrial supplier or local fabric store? Did you color taint the poly or is that the color of the fabric. Don't worry about the wrinkling... it wil go away or just simply not affect much other than looks.
Scott