FWIW, I only see ghosting in theatrical screenings when at horizontal extremes [aisle seats], but vertically, it can be as little as two rows from dead centre.
Not only that, but when seeing 3D anywhere, it tends to be the case that the further you are from dead centre of the screen height-wise, the more ghosting you see. Also applies horizontally, but to a lesser extent. When viewing Puss In Boots: The Last Wish earlier this week in cinemas, I...