If I read it correctly, the mapper will score fingering based on how many frets the hand needs to stretch:
https://github.com/scottvr/gtrsnipe/blob/4cae149e1dac766c3c3...
But this doesn't seem to account for other shape concerns. The bit I am most interested in is whether this mapper can avoid barre chords where possible.
Related, I think there should also be an option to take capo into account.
There's quite a bit more involved in the scoring, such as string hopping, runs on the same string, etc. I invite you to run --help and look at the mapper config tunables. Ideas for improvement are welcome.