When I gave her gas she seemed to hesitate around 4200 rpms. Flat spot 550's are known for?
Maybe/maybe not.
Wouldn't it be nice if you were told whether the "hesitation" throttle position was running lean or rich?
Wouldn't it be nice if you knew at what precise throttle position (slide position/jet needle position) the "hesitation" occurred? (Mechanical slide carbs have no knowledge or appreciation for engine RPM. They know only air speed and vacuum parameters and respond solely to that.)
Wouldn't it be nice to know what air bleed screw setting was selected?
So, without a dyno's exhaust sniffer, observing spark plug deposits while at the "problem" throttle position might indicate what is happening inside and what the engine needs to correct the problem. This is done with clean spark plugs, a test track, quickly attaining the problem scenario operation mode, holding it for a time period, and then killing the ignition, pulling in the clutch, and then reading the spark plug deposits.
I had the gauges set all the same. I saw XSMOOTHs video of his sync and his gauges read higher. Should I move it to where is are?
No. It is a vacuum balance activity. Actual vacuum level after balance is related to engine efficiency and idle speed. Once balanced, it is what it is. The carbs do not produce the vacuum the engine does.
Cheers,