Thanks! I was also able to get the fin pattern (From The SM-3 Seahawk on JimZ's site) My tubing is a little over at 1.85 ID (Xmas Paper tube)...
I know I cant Get the knife edge of the plastic originals but am thinking about going with a center spar and skins for the fin profile...(Comic Book Backing boards for the skins)
Your ideas on the fins should work. The Estes Pro Series Patriot (2066) used a similar method to get the scale airfoil on the fins. I hope you have a lathe to turn the nose cone.