From what you are describing you have two doors in one jamb unit, you can't trim the width of the jamb. You need 62" in width and 82" in height for the rough opening to fit this door. If you take the drywall off the inside edge of the studs, you'll gain an inch and be at 62", which would be fine. If you take the drywall of the top of the opening, you'll gain a 1/2" to take you up to 81 1/2". You could trim 1/2" of the bottom of each jamb and fit the door in the opening. You'll lose that 1/2" in the clearance between the bottom of the doors and the finish floor, which may or may not be an issue, depending on what kind of floor you have. If you needed the 1/2" back, you could trim 1/2" off the bottom of each door without affecting the integrity of them.