We have solved MANY "hesitation from idle" issues by REDUCING the idle fuel (turning the mixture screw in).
Often, enthusiasts use a vacuum gauge, or set for the "fattest" idle which is too rich; and causes puddling in the intake. Cracking the throttle increases the air velocity in the intake, sweeping all the "puddles" or droplets into the cylinders creating an instantaneous over RICH condition and hesitation.
One screw at 1 1/2 turns is generally too much unless the engine has a radical cam.
Two screws at 1 1/2 turns is more than one screw at 1 1/2 turns.
Jon.
