One final note from me...
Clay will not clean the paint like a good chemical paint cleaner. Sure, claying will clean the stuff on the surface, but nothing below the surface.
To create a pristine paint finish that will allow "ANY" LSP to look great...
The paint must be as clean as possible - This is where the paint cleaner... and yes, claying come in to play.
The paint must be as free from imperfections as possible (like swirls, scratches, water posts, etc.). This is where mild to aggressive polishing comes in... and the previous paint cleaning.
The paint must be as smooth as possible - This is very final polishing comes in.
For many, many, many years, (hint about my age

) I manged to do some exceptional detailing without the help of clay. That's not to say that clay isn't a good tool.. it is! However, it doesn't replace a proper paint cleaning. Claying should be another tool to "aid" in the paint cleaning process.
Done with rant.