Cobalt has been prepacked as a theme, but many of the available icons for the dock are not.
So the way to use FauxS is to unzip that package to its own directory in your OD folder and then manually apply whatever you want to use from that pack. You'd create a new shortcut, then rightclick on that new icon, go to icon properties. You'll see a change image button there. Then you browse to the FausX folder and find the icon you want.
Now you can package and save your own themes in the OD configure panel. Under the themes tab, you can save the current dock as a custom theme, or package it for distribution.
I think most people kind of mix and match the dock icons.
