[Piotrsko]

Unless it has a source switching scheme, those different scales have to be interdependent. Rules of thumb so to speak. Not fluent in the use of a vacuum gauge for economy, understood the theory not the practice. Do know the system vacuum drops like a rock when applying brake in kinda a linear fashion to stopping force, but that's theory not experienced. Hate vacuum brakes, no pedal feel. Long throw mechanical you can sense the point where the tires are about to skid.