So, I used the alt trick and tried to add in 3 custom fonts, Charis from jswolf, Gentium book from blossom, and Caecilia that I modded myself.
Charis and Gentium both look really nice, but aren't suited for the size I like to read at. I have been reading on the PW with Caecilia at size 2 (from left) and when I use Charis and Gentium, they are both too small at that size. Gentium book looks better to me up at size 5 but is a bit too big and size 4 is a bit too small. Maybe it is just the way the font is designed with the unique tall l's and h's. Charis looks really nice at size 3 and gives the stock Caecilia good competition.
So I tried to use the same custom Caecilia font I used on my old sony 505 with regular = semibold, italic = semibold italic, bold = bold, and bolditalic = bolditalic.
Here is a post with a photo of how bold the regular looks on the 505 (sorry, there was no way to get a screenshot).
On the 505, it looked pretty good, and even better on the 650, but on the PW, it looks horrible and super thick with nasty display characteristics. I tried to get a screenshot of the modded Caecilia on the PW, but I managed to freeze the PW and was forced to long hold the power button to reboot.
Before trying to change fonts again, I deleted the modded Caecilia to prevent freezing. I suspect when I modded the metadata with fontographer, that the PW didn't like the changes I made.
Anyways, if someone makes a slightly heavier Caecilia but same size as the stock Caecilia, please post some pics and what changes you made so that I can reproduce your results for my own use.