Since the rhumb line is on the Equator side of the great circle this must be the northern hemisphere. If the conversion angle is 3º then convergency is 6º. If the great circle track from A to B at B is 080ºT then at B it is 086ºT. If the great circle track from A to B at B is 086ºT then the great circle track from B to A at B is the reciprocal; 086º + 180º = 266ºT.