oh one other thing i forgot. where do the two vacuum line that come off of the center carbs go?
Those are fuel tank vents. I'm not certain about your model, but on the Cb550s they have hoses that route back and down between engine case and swing arm pivot. Anyway they should route to the same place the carb cowl overflow hoses go.
As far as your jetting goes, you have four things in each carbs to tune, Idle air bleed screws, Idle or slow jets, Throttle valve needle height setting, and main jet.
These all control mixture at specific throttle settings. See chart below. Without an exhaust gas analyzer, reading the spark plug after operating under load at a specific throttle setting is a way to tell what combustion conditions you have and which way the settings should be changed.
Fouling plugs is usually caused by running way too rich. However, it is possible to set up carbs to run rich near idle and lean on the throttle valves and rich at WOT.
Other things that can effect carb settings are exhaust and intake restriction and their magnitude mapped over the RPM range or air velocity range.
Cheers,
