I believe cheap servos are inherently very discrete due to noise in the "potentiometers" used: it will not be possible to do precise positioning no matter how e

I believe cheap servos are inherently very discrete due to noise in the "potentiometers" used: it will not be possible to do precise positioning no matter how exact your timing pulses are. But thats just a guess. If its a noisy potetiometer/wiper but monotonic it should be possible to correct in software. If its non-monotonic and has reverses gradient it will be much harder or impossible I guess.