I am just having a hard time understanding how you steer with ailerons while keeping the wings level and how does throttle keep you on centerline. If you are saying use more throttle during the crab to stop the drift or allow more drift then that would be very counter productive. The best way to fly an approch is to establish a safe airspeed with trim and use throttle to adjust the glideslope. Use small heading changes with coordinated turns (aileron, and rudder if needed) to maintain your approach path on the centerline.