Sorry, sorry i keep forgetting this is a cold start problem isnt it, ive got a boosting problem in my head.

As for your vacuum gauge, -5psi seems low.

When you crank the car u should see the flap moving up and down ever so slightly.
Does it run ok once you eventually get the thing going? (if not what is the vacuum gauge reading and is it stable?)
Does it re-start ok when hot?
Have u checked its maintaining a fuel pressure? (if not do you know how to)
Have you got a dump valve?

Sorry to ask so many questions, hopefully i can help you, but im sure the wiring isnt your problem