Actually, yeah, that default scaling definitely looks wonky on 6" 300dpi Kindles (i.e., Oasis 2 excluded), it should probably be 3, to end up w/ roughly 45 columns.
I've been spoiled by the larger screens of the H2O & the Forma, while my PW2 is only 212dpi

.
I was somehow under the impression that there'd been a few 7" Kindles along the years, but, nope, everything was 6" until the KOA2. >_<".
If you could provide me with a screenshot and the terminal output from something like
Code:
fbink -Mmp 'Wheeee!'
that'd be helpful

.