I've been running a few tests yesterday with different settings and it appears to not make a huge difference
Just to see what happened I tried Fontsize 9, Linespace 0, Char spacing 1, Landscape (confuddling to the max) and hte end result was identical.
The only option I found that affects the way it looks was the landscape mode. i'm assuming this is intended for chinese texts with the vertical reading.
Once the STK is on the device it appears that the look is up to the device and not the STAReBOOK.
On another note, reading comics on the thing is quite funny. There's a few to download off the book store thats part of the eRead software. As in you can actually get the STK files for them,
micro