If you didn't back up your XF86Config file in the previous section, do it now. For example:
root# > cp /etc/X11/XF86Config /etc/X11/XFree86Config.working
One card at a time manually configure and install each video card/ monitor combination you are going to have in your final setup. If you have several identical video cards you can get away with configuring one and copying the configuration for the other cards.
Note, it is possible configure and test your video cards without physically swapping them. If you use the technique in Section 6 below and specify the bus ID.
After you have each card set up, back up or print it's config file as you will need it later. Here's how I did it:
root# > cp /etc/X11/XF86Config /etc/X11/XFree86Config.Matrox
If your video cards are identical you can probably get away with just one copy. However don't skip this step, If all else fails this will be you backup config file incase my instructions lead you astray.
Once you have all of your displays configured you are almost there...