Jed - I don't want to pour cold (sea) water on your sterling efforts, but for someone to call a Royal Navy captain of that (or any other) time a 'privateer' was a very great insult. O'Brian points this out in his books when 'Surprise' ships a crew of privateersmen from the (imaginary) village of Shelmerston, and the shame Aubrey feels when he was out of the Navy. Even he preferred the term 'letter of marque'. Privateer might have been a term that was acceptable to Drake and Hawkins, but to no one after that period in the English/British service. I'm trying to find a modern day equivalent - probably like calling someone who serves in their National Armed Forces a 'mercenary'.
The correct term for a career naval person of this time (other than officers who were Naval officers, or officers in the Navy) was Man-'o'-War's-man. Many songs of the time use 'Captain bold' or 'bold Captain'.
Hoping that this helps rather than hinders, Les