Hey Julie - where'd ya go?
In my opinion, the hardest part is deciding just how you would adjust the various settings, e.g. after an auto-tone.
Can you specify exactly? If so, it might be possible to translate it into a custom Gazoo preset...
I've toyed with the idea of pulling (jpeg format) image preview data from Lr and submitting it to image-magick to extract histogram data which could then be used in a "feedback" loop, e.g. to set a black/white clipping percentage, but I've not done such, for example:
1. auto-tone
2. get fresh preview/histogram data
3. compute percent black clipping
4. if not enough, decrease blacks some more, and goto step 2.
5. if too much, increase blacks and go go step 2.
6. similarly for whites.
I'm curious what you have in mind(?)
Cheers,
Rob