I like to think there isn't a best performance of this piece, or others like it in our repertoire like the Nocturnal, say. I've heard vastly different performances which I like alot, but they don't ring true to the way I want to perform it. I think they whole point of being a performer is to bring something new and personal to the piece. When I've had masterclasses on this Chaconne, the performers can have wildly different conceptions of it, and they will outline theirs, before helping me to work on mine, and on bringing out what I want to achieve better. The best lessons I've had have been exchanges of ideas rather than being told what to do where, and usually I can find myself thinking halfway through a when a teacher is suggesting something, that I can complete the sentence and think "of course, that makes much more sense to me now!"
The more I've got to know the piece (I played it in my final recital around this time last year, and have had various gaps of 3 months before re-approaching it), the closer it has come to my final conception of the piece. The notes are pretty much set now, like the added basses and how I'm arpeggio-ing, and my approach to the piece is unlikely to radically change, just evolve and grow, for instance I'm not going to decide double dotting is the way forward all of a sudden. That doesn't mean to say I think my approach is the best way to play it, just the one that makes most sense to me and my playing and personality. And if I'm confident in performing it the way I want to, not thinking about judgement or comparisons, the audience can feel that, relax and let themselves be taken into the world of Bach how I imagine it.
Quite tough to put into words, but I hope that helps you understand Ari! And thank you for the kind words too, I love Heifitz, but I prefer a slightly straighter version of Chaconne like Rachel Podger's. Completely different approach from a different time, but there's something out there for everyone to enjoy!