Hi,
Why not use the product you're working on ?
I personnally store my changes in PDMLINK itself, with proper documentation,which takes care of revision control. You have the choice of doing it on your testmachine or onyour production system.
I use a dummy Product which is visible to admins only.
One way to improve this (but that I did not implement in PDMLINK) would be to create a product structure that maps to the locationsin the windchill tree which you modify. You could use a special type of part to representin PDMLINK directoriesof the real life system. I gather that it would then be possible to create a tool that would walk that tree and build the installable structure for you.
This has worked for me when I was doing heavy development on another configuration manager product. I did not implementfor PDMLINK because I only do light customisation on it.
HTH,
Vincent