While we all despise P.S. letter editor, I have custom 1040 letters that I use for every client.  I prepare my final version, copy and paste it to a Word file that I save in a Documents folder.  The following year I copy and past that saved file into the new P.S. letter file, replacing what P.S. has prewritten. Once saved in P.S. as the master you don't need to worry about Common File folder and Rich Text Files.