Carb Synk

I Borowed some guages and I was going to attemt to sync the carbs on my 1980 kz650 with them. I hoping that someone could give me some pointers.. What should the guages be reading as far as pressure? these gauges are in inches

At idle speed (about 1,000 rpm) the vacuum should be between 19 - 24 cm Hg (7.48 - 9.45 inches of mercury). The most important thing is that all 4 readings are very close to each other. The difference between any 2 cylinders should be less than 2 cm Hg (.79 inches of mercury). Hopefully the tool you borrowed consists of 4 gauges and each gauge has a little damper valve near the base. You adjust the damper to eliminate the needle bounce caused by the cylinder pulses as the engine runs. Ed