I at this point do not say I am piano tuner. I do tune my own.
I had a great tuner that tuned by ear and new how to set the pins correctly, but he has retired.
The main reason I decided to tune my own piano is due the the disappointment of the tunings I got after my local tuner retired.
It's really a bummer after you pay $125 to $175 to tune your piano and a day or two later you end up with three or four sour notes
I would say that after your done tuning that you play the piano and play it somewhat hard to make sure it will hold its tuning
I know setting the pins is not easy , that's why I don't do it.
It is not difficult but imply a long training to perceive the motion of the wire and the one of the bottom of the pin (thru the tuning lever, but the ear is used of course) .
Probably 80 % of the tuners are "shooting in the dark" and need to evaluate their setting with test blows.
Learning to evaluate the springiness of the tuning pin is necessary, and allows to leave all pins under the same stress ;
if not there is a range of acceptation where the pin grips in the block, but the residual stress varies.
Usually in a good tuning, octaves are out of tune before unison. This is also because unison have a range of acceptability, but strong unison are stable, and tend to stay put because the attack energy is well regulated in a "less trouble path" , tend to stay or go back there
Setting the pins with hard blows can work, but active setting is more efficient. When firmly set a wire can be pulled with a wire hook without changing.
To tune a piano , one must not be afraid by the wire, then one need to be confident enough in its abilities, that is why so many tuners consider themselves as really good, and avoid any self criticism. Sort of "if you hear it sound good, it must sound good"
Customers that make difference between the tuner's tone are very rare. Some may even like moaning unison's , but some are really embarrassed with them.
Control on the tone attack provide control on the dynamics of tone the attack may energize the fundamental and couple the partials at the same time, the rest is a question of proportions. (because strings have differences in iH and spectra, generally)