Need help syncing carbs on GPZ 900

We are attempting to sync the carburetors right now however I'm running into a problem. I understand that there is for vacuum lines that run to the sync gauge however the port on the number two carburetor is vacuum for the gas tank. Is that where I hook up the line for the number two carburetor? I was thinking that that would kill vacuum to the gas tank and fuel would not flow while syncing the carbs. I was able to hook up 3 to the gauges but they are jumping around erratically when making adjustments. There is only 3 adjustment screws while syncing, correct? They are the screws between each set of carbs? Any ideas? Thank you in advance.

Yes, you must disconnect the vacuum line to the petcock to hook up the tool for synchronizing. If you are going to use the fuel tak instead of a remote tank, put the petcock on PRI.
If your guages are jumping around, they may need inline restrictors.
You have already adjusted the valves, haven't you?

Thanks man! We just got him synced up perfectly.