Since you mentioned Bach. Bach can (should?) be played in a class of temperament knows as "Well Tempered". The main idea is that unlike just intonation, well temper allows all keys to have somewhat pleasing intervals but unlike equal temper each is unique from being more consonant at the top of the circle of fifths to more dissonant at the bottom.
That is very interesting. I didn't know that the WTC was meant to be played in well temperament. In contrast to what you said, the article states that 'The adjustment in cents from equal temperament is as follows, rounded to the nearest cent. I've been told that tuning any finer is too difficult.' You think maybe the tech just wanted to get the job over with?
In some Kontakt instruments, you can select from a number of different tuning systems. The thing with the article is that the well temperament we have today isn't the same as what Bach might have used. Even if it is, since it's asymmetrical, we don't know whether he used C or another note as a root. Even then, it's likely that his piano was tuned some cents more flat overall since we know that A4=440 is only a modern convention.
Taken together, I feel like the EQ system I came up with is pretty good. I was using the Waves Q1 yesterday and, like many EQs, it quantizes your input value. In other words, I can tell it 65.41Hz for C2 but it'll just do 65Hz. While I definitely intend to revisit the chart, all this talk about temperament, tolerances & quantization really has me thinking it's unnecessary.