Flew this a hundred times over the years. Typical TEB ILS6 circle approach instructions have you start circling at TORBY (1284'msl on the glide slope of ILS 6) at 3.8nm from the rwy 6 threshold. Even when you initiate the circle in a timely manner, with strong NW winds, this maneuver is very challenging. The rwy 1 threshold is also displaced closer to the circling radius.
KTEB 151952Z 34016G30KT 10SM SCT045 19/04 A2976