I think only the original CMS is the best package that makes use of CR. This is because the author of CMS and CR are primarily Karl G.
I am trying to make the best of my efforts in putting the most common operations in bcms. But then its not really a package, just tcl api for me to use for my packages.
ETP is a good package to understand how the tables relate to one another, and its small and simple enough. But it does not make use of CR properly. File Storage and its UI is close to what is happening logically on the CR.
Granted that it has reached the 4th request, it goes to show that there is no real reference package as of now. Also we do not have Karl G's opinion in them. So we left to our best of efforts to understand the code and docs. I think as more people will try to understand and use CR we should come up with something in the future. Just share your notes and info so others can see.
