> This makes me wonder how I should use the "unallocated" space I have on this 16GB card? I could add a little to both, I guess.
Ken, you can write image to SD card and then resize KoboReader partition with resizing tool that supports Linux partitions (gparted for Linux or MiniTool Partition for Windows). Please take a look at this excellent post:
https://www.mobileread.com/forums/sho...d.php?t=209122