As per Tksuoran's suggestion, I've added Kerning pairs. These are calculated for both ordinary and texture fonts at load time.
The results are great! I can't believe how much better it looks, and I'm slightly shocked that I this slipped me by in the first release.
Here's a before and after image:
 On second thought, justified text is probably not the best demonstration for kerning pairs, as extra pixel gaps are added / removed to get lines to fit anyway. Still, I think you get the idea, particularly with the severe ones like the "ro" and "ct" in the Introduction heading.