Yes, font fix thing doesn't seem to be working. The "instructions" aren't really all that clear, so it's difficult to know if I'm doing it right. I just copied the fontconfig folder to extensions, removed all the font names I didn't want from fonts.txt, then used the KUAL button to hide fonts. After restarting, all the fonts are still there. So I'm not sure what else I should be doing. There's some cryptic comment about the KUAL button overwriting the config files every time, so I'm not really clear on how this is supposed to work.
>edit: oh wait, think the fonts.txt file is supposed to be the fonts you *don't* want included. restoring that and restarting...
Ok, my mistake. Verified working on Paperwhite 5.3.3