I found several pages that talk about installing and running compiz, and a general overview of the sections contained within, but it's difficult to find documentation on exactly what we're editing in each node. For instance, there are fields labeled "Clone Output" and "Window Previews", and I can't find any information about exactly what those do. Is there a place where all of these fields are documented?
Try these... Compiz Wiki CCSM
These pages have been around for years, and are likely to stay around.
Here is the page for "Window Previews"
On the other-hand, it doesn't have any thing on "Clone Output"
And good luck!