Thanks so much for the reply!
1. I was thinking KUAL could be used to adjust/specify the screen coordinates of the hack's output, but from your description, it doesn't seem feasible (at least easily). I'm using (hopefully) sane defaults, so it could be skipped for now. Or maybe some sort of conf file instead..?
2. The configuration file will only change during install/uninstall.
Hmmm... I guess I'd be happy enough with just an update*.bin for now. I actually just found NiLuJe's KindleTool thread
so I'll practice that first, and work my way up.
Thanks again!