Before the carb sync I had slightly more vibration in a certain rpm range nothing serious just slightly more . it was around 65 mph in 5th gear. I'm sure that my bike was within specs on the sync (40mm Hg) I don't have the actual reading because I'm not using a gauge.

The adjustment I made to the sync screw was very slight and only moved the fluid about 1/2 inch in the tubing but that was enough to get the bike to run even smoother in that one rpm range .

I always considered the T to be a very smooth running bike but now it's even better.

One thing worth mentioning is if you use an oil manometer, restrict the tubing size so that you don't have large fluctuations in the fluid. I'm using tubing with an inside diameter of 1/8 inch and it seems to work well