I'd add it at bottling. Yes, you can mix it in a little vodka to sanitize and pour it in. Also, you can boil a cup of water and add the spice to it while it's still boiling hot, let it cool, then add it all to bottling bucket.
Edit: I originally referenced the OP's reply to his own thread in post #2, not realizing that it was the OP's reply. Changed the wording in my reply to clear up the awkwardness of my original reply.