Frank,
I'm curious what design or plans you are planning on using for your frames? Original design or rectangular tubing? Stressed and tubbed body or non stressed body skin?
IRS rear or live axle?
Suspension set up for street or track?
You can get an awful lot of information on this board from guys like Alex Avenosky, Morris, and quite a few others with a little information.
Lots of guys use the Cobra Restorer's plans for their scratch built cars, mostly because of the original style of it. Many of the newer kit manufacturers have gone to rectangular tubing, I'm assuming for ease of manufacture. Each has it's own merits, but each requires a different suspension design for proper geometry and handling.
I'm not sure a bolt-in suspension cradle like those designed for hot rods will be the optimum set up for a Cobra, especially if it will be used on the track.
The Cobra Restorer's plans have the suspension mounting points in place and designed for the original style suspension. Others have pick up points designed for either Mustang II suspension pieces or their own proprietary designed pieces.
Just curious which direction you're planning on going? Yeah, I know, none of my business- but I'm curious by nature (some say nosy?)

- Bob