It would be easy to read this from user defaults instead, though you may also need preferences as to how to truncate a title.
Tinkered a bit myself yesterday with the source, it sort of worked, but I always seemed to break the layout in some subtle way (I guess it didn't help that I didn't quite understand what 'tabViewSpacing' does exactly). So when I noticed the brandnew build with the new user default settings I felt a bit stupid.
Seriously though, thanks!
One last question if you allow: minimumTabSize and maximumTabSize don't behave exactly like I initially thought they would. For example, setting minimumTabSize = maximumTabSize = some_value made me expect all tabs would now be of identical (horizontal) width, at any time, but that's not the case (long file names still get wider tabs than what is set in maximumTabSize).
That's by design I assume, as in: maximumTabSize only kicks in when the tab bar overflows. Did I get that right?