South Atlantic Random routing
The airlines crossing the south atlantic file random routing, depending upon the winds, inbetween the entry and exit points of the respective airspaces on either side. Check the Jepp and NOTAMS for required entry/exit points on either side of the Atlantic. In my opinion, your routing seems good, although I haven't checked the Jepp and NOTAMS, "Terba" is used by many a/c leaving FNLU airspace over the water. Hope that helps.