[library addict]

I do have a Source column in my Calibre Warehouse library. I only have the books, basic metadata, series info, etc in that library with the original books (without doing anything to them). Then I copy the books to either my main library or my vault library which is where I add the book's blurb and process the books to remove excess front or back matter and fix the css as applicable.

My vault library also has a "Date Archived" custom date column.

For the warehouse library the Source column is first and for the vault library the Date Archived column is first. This way I know at a glance which library I am in.

I like that the Date Read and Read (Yes/No) columns copy to Calibre Companion. So I can see the green checkmark by books I have already read when I am looking through my library on my Nexus.