Dennis,
I have a pair of the original-style rear mounts you can look at if your CAD prototypes don't turn up the way you want them.
It's nice having the Shelby museum nearby to reference an MKI, II, or IV, isn't it? Did they let you go behind the ropes to take your shots? Sometimes they do, sometimes they don't let me behind the barrier so you have to get a little creative with your camera and shots.