Buck and Rich!
Thanks for the compliments!
So you want to use C5 parts. My guess is you want it to handle like a 'Vette? You have the gear to fab it. Now you just need to go measure the 'Vette of your choice. You'll need to transfer those measurements to your friends car and start deciding what you'll have to change and where you'll need to compromise. I would say that if you are going to design your own front end you probably want to start at the spindle and design from there. Track width will have to be narrowed. Since you're doing custom fab are you going to lengthen the wheelbase? What ride height are you going to go with. Airbags? If you don't want to go to all that trouble then I would suggest you find a car with a Chris Alston or Morrison clip and and take all the measurements you can from there. Analyze it and change whatever you think you can make better. I hope you know suspension engineering because for you to optimize it you'll need to know. Even a 1/4" off somewhere will make the car drive differently.
Good Luck!
John
P.S. You should look at Jasons(slow4dr) build too! He's using a C4 'Vette front end! Lot's of good info and engineering going on there!