The freighter fleet only hires F/O's. All applications through Cathay Pacific mainline.
Having said that we sometimes see S/O's on the frightener.
F/O's with the right amount of seniority and experience get promoted to the dizzy rank of Relief Pilot (or whatever they call it this week). For this act they are awarded three full stripes but no extra money (or very little?).
Due to a lack of Relief F/O's (They are migrating to the pax fleet after their 3-year sentence on the frightener) it is quite common to see Relief Captains on a crew.
Extra aircraft coming so get your names down with Cathay.