Here's a file that compares manual to power brakes.

It looks like it takes the surface area of the booster and current vacuum to calculate the additional pressure provided.

Then it has two lines for each manual and power so you can compare different sized MCs. I think the table on the right is different foot pressures. For power it then adds the pressure provided by the booster (I think it's looking at the 9").

Although I think it needs to take into account pedal ratio somewhere in there

As always, use this at your own risk

edit: cleaned up file available a few posts down