I do know what xorg.conf is
It is a text file which contains the configuration for the X server. Each screen is defined there and so on.
Also look in the man pages.
If you search these forums of "xorg.conf" you will get many examples of diffeent working and broken configurations.
Basically you have a lot of reading to do
You are probably thinking that the possibilities of dual head are horribly underutilised. You are right! We are being hampered by the fact that mostly windows users use dual head - and they only get one workspace anyway (they don't even know it is possible).
The settings for your windows manager are kept in your home directory.
You should realise that the different workspaces (available from the workspace switcher) are "virtual desktops" only. They are all open all the time.
It sounds like you are trying to do something the hard way though ... why not have n workspaces on one screen and 8-n on the other ... and use x2x to shift the focus. This way you open apps in whichever screen you like - sliding the mouse from one screen to the other at will. Isn't this more what you want?