I'm afraid I was too chicken to attempt that when I rebuilt my car. Besides, the electrics weren't that different from the stock wiring. Certainly not as drastic as adding a Ztec (assuming you're using injection).
One thing I saw someone do was wire his dash separately. In other words, he had a plug screwed to the back of the dash that everything was wired to. The loom behind the dash had the mate that connected everything to the proper wires. I thought that was really nice!
I might also advise that you increase the size of the grounding wires. In fact, you might try to gang them all together wherever possible so you have fewer places where you would need to check for a ground problem.
I met a guy at the LOG last year who ran the power through solenoids and the switches just triggered the solenoids. I think this was mostly for things like window lift switches. This way, the switch had less power through it and the solenoid took all the juice. I thought that was a good idea.
In spite of what you might think, Lucas had a very complete wiring color standard that can be very helpful. I don't know if Ford has the same thing. If not, I would try to keep with the Lucas standard knowing full well that whatever wires you have on your Ztec will not keep up the standard. At least that way you have part of your wiring to a standard that can help you if you don't have a wiring diagram handy.
I don't know if that is helpful at all, but it's the best I can do
Good luck and keep us up to date with how it goes!