twocats
Regarding fixing a few notes. If you can hear unisons well enough to tune a guitar against the tuner and not have any wobble, you can tune a piano string too. It's a matter of hammer technique - an art as our technician friends will tell us, and rightfully so - that gets better with practice.
May I suggest that rather than tuning against the tuner (which will not be tempered?), you tune against one of the three strings if it's a tri-chord, one of two, if it's a bi-chord. Depending on which way your piano has drifted - up if the relative humidity has gone up, down if the contrary - press the key down to lift the damper - then use your guitar pick to strum each string. Pick the ONE that is most likely right - mute the other two - and listen for a quiet 8ve, a 5th that beats at less than 1 beat per second. Having found that ONE probably correct string, tune the others BY EAR to that one probably correct string.
Regarding hammer technique - LESS (movement) is definitely MORE. Small movements should be enough. The pros will do a few other things to equalize the tensions of different parts of the string in addition to rotating the pin. They will push down on the hammer and listen, sometimes they will push UP on the hammer. Point is they are getting non-speaking lengths of the string to settle in and stability will help.
Anyhow - you CAN do it sometimes just with straight on lateral rotation.
Please let us know if this helps.