Hi, you may be interested in this Instructable where I have published my solution with kerned proportional fonts.
Fonts have been added to the Adafruit_GFX library and it has been renamed Adafruit_GFX_AS
If you use a different display driver library then you just need to change the references in that library from Adafruit_GFX to Adafruit_GFX_AS.
Cheers,
Alan