"beef up" PRS300 fonts?

Hi, revived my PRS300 recently after my nook Glowlight+ bit the dust. The fonts (all epub files) seem pretty thin and low-contrast. I know it's an older e-ink display technology, but is there any way to make the letters thicker with better contrast?

I have PRS-Plus installed, poked around the menus a bit, didn't find anything helpful. Suggestions? Thx!