Move step five to before step four -- Find Duplicates can compare two calibre libraries. That way, you don't have to commit to changing the new library at all (and you don't *have to* back it up).
Also, in step four, you will probably see your new library already listed, since calibre remembers it from when you first opened that library.
Other than that, you got it.
Tell us if you have any problems, or report back on your success.
