Hello Stefan,
There are about 23 parameters that may be edited note-by-note in the PRO version. Here are some of the edits I regularly make on all of the different piano models offered by Pianoteq:
Tuning: Instead of using a Stretch tuning slider, I make my own in the PRO. Usually, in the bottom 1-1/2 octaves, I create a curved "line" of tuning individual notes made deliberately flat from -0 to about -10 cents. Usually, in the upper 2-1/2 octaves, I create another curved-line note-by-note progression of tuning made sharp, ranging from +1 cent to about +22 cents.
Unison width: As a piano tuner, I am familiar with ways that pianos go out of tune, and how comparatively difficult it is to tune the unison pitches of certain ranges of pianos. So, in the PRO version, I regularly REDUCE the unison tuning in the lowest octaves (because there is only one string per note in this range), and I increase the unison tuning in an upward curve for the highest ~2 octaves (where it is more difficult to tune these notes by ear, in the first place). Next, in the upper bass, "tenor" portions of the piano, where there are changes from one string to two strings per-note, and then where it changes to three strings per-note, I make a little "break" upward in unison tuning. Finally, in the middle two octaves, I raise the level of unison tuning per-note, because this is where the piano is usually played the hardest -- therefore I slightly raise the overall unison tuning in this area.
(Still on Unison tuning) After these fine adjustments are made, I click on the unison tuning "random" button -- different in the PRO version than in the Standard version, the latter of which is much more coarse in its randomization amount.
Hammer Hardnesses:
I tend to increase the hardness in the range of the three octaves, because this is usually where the most wear normally occurs in a real piano. I do this separately for the three individual hardness ranges. Next, I randomize them slightly. This helps to reduce some of the "excess perfection" in the piano.
I also perform other edits in PRO, but this gives you an idea of how I think and work on my pianos. The results of these efforts often show up as that "something extra" in my demos.
Hope this helps,
Joe