I think that if you are having trouble getting good curves you should consider the focus direction and appropriate backlash compensation - as I described. Those things are important even without autofocus - when focusing an sct with the primary mirror. Adding something like a feathertouch to the focuser knob won't change those issues.
The details I described may be a burden when getting things set up - but they are important for getting good and consistent results. Once you get it working it is automatic and shouldn't require any more tweaking.
Frank