Synching TBs underload?

On my KTM SD the tbs are really sensitive, maybe moving the adjustment screw1/16 of a turn causes my manometer to move a few inches.
So I took some time and got them synched up pretty good at 4000rpm.
On the road it was still buzzy??
I attached a large nut on the adjustment screw so I could reach down and fiddle with it while riding.
HMMM
It took just 3 or 4 runs down the road and not turning it more than a 1/4 turn the bike is velvet smooth.Its never been this vibration free, its like a different bike.
Curious I went home and hooked it up to both my tune ecu which takes readings of the individual airflow on each tb and my home made balancer.
Both showed the tbs to be way off???
Well Im not touching the thing now, the bike runs great.
So just how the frig are you to set the TBs and why is mine so different under a load?
Bigger question is how does a dealer do it?

That is interesting. The manual says you do it at idle, with the bike fully warmed up. The IAC will jak your readings if the bike is cold and IAC is compensating.

You did by feel, when riding? I would not necessarily correlate seat of the pants "smooth" with running optimally. For example, I can richen up my idle mixture to make the bike run fat, and it seems very smooth……but it’s lazy.

The synching is adjusting the opening of the rear throttle plate via a screw adjuster.
As far as I know it does not alter the fuel mixture, maybe someone in the know can chime in??
I was thinking smoothness is directly connected to both cylinders putting out the same power, maybe Im wrong on this.
Anyways, the amount I moved the adjuster screw is miniscul, but it had a great effect on smoothness and the motor is a much nicer ride as a result. I can say after owning way too many bikes this LC8 motor is sensitive to this.

I usually adjust my Tbs at 4000rpm when the motor is warm as i dont care about a smooth idle. Again when you do this usually there is only a small difference from the adjustment at idle.

My buddies say Im to anal, probally they are right LOL