Dean, just a note to tell you I built something simular. I ended up with a Rotary lift, but the drive up platform was and still is, the winter landing area for my Cobra.
I got a lot of good info from you and your design, thanks!!
BTW, if you use 2 x 12 material, you can change the clutch on a Cobra without jacking the car up, I know I did it using Dean's platform design.