Boost Pressure at Cruise

I have a Rotrex C38-71 on a 5 liter v8. I have it running and am presently fitting instruments for tuning.

The Rotrex is a ball drive centrifugal machine.

I wonder if you have a similar set up,
e.g.

blow through MAF,
centrifugal,
5 l,
V8,
10 to 1 CR,
Normally aspirated cams
...you could tell me the sort of boost pressures your are seeing at what might be

low cruise 50 to 60 mph and
high cruise 80 to 90.

My research so far tells me to expect

10 inches Hg vacuum at low cruise and
running just positive boost at the high cruise.
I am wondering if I will have enough vacuum to power the brakes.

Thanks

James