Chris,
This is a subject that I have spent way too much time on in the past and I could probably talk around this until I had you completely confused.
For issues strictly involving Fedora, I personally use a completely different Forum. I would never try to pull users from this forum for any reason, but I will direct you attention to a thread I had opened over there in the interest of hopefully letting you get a better handle on how the file works and hopefully what you can do to further your efforts.
One thing I might suggest to see if it can easily be fixed is to try running, as root, system-config-display. You might be surprised to find that you will find a generic setting in there that will suit your needs.
If not, you might want to go look at this thread for more food for thought.
http://forums.fedoraforum.org/forum/showthread.php?t=77709
"I expect to pass through this world but once. Any good, therefore, that I can do, or any kindness that I can show to any human being, let me do it now. Let me not defer or neglect it, for I shall not pass this way again." Stephen Krebbet, 1793-1855