[Gaz64]

I would think about adding a fuel pressure gauge, just for testing, in the cabin.

The reg could be referenced to the hat, so fuel pressure would be say 6 at idle, to 12 under boost.

Where as to manifold vac, it would be say 3 at idle, 6 at zero vacuum, and then 12 etc.

Depends on your current vacuum at idle, (camshaft), and how much boost you are running.

You could also reference the regulator T'eed with an adjustable bleed to the carb hat, then can you dial up what your fuel pressure curve is separately to boost.

Gary