Hi ABomb, I see this topic is still alive, that's good
When I installed ET I just let all the options by default. If you didn't enter the root password it'll will install it on your home dir, not for my case, but I do remember somewhere during the installation mentioned two folders (I didn't modify) one regarding where to install the game and another for what ever, don't remember though.
Regarding where ET stores your config, I think it's located under your home dir but it's hidden (remeber dirs. that start with a '.' aren't listed when you use ls, unless you indicate it), it's something like this:
/home/your-name-here/.etwolf/etmain
There is located the etconfig.cfg and other files.
In addition my xorg.conf file is like:
16bit: 800x600 600x480
24bit: 1200x1024
So the affirmation that if you've got only one resolution there you will obtain the small screen isn't true.
Hope it helps
- Cheers!