Having had a N450 my self, the trick is not to loose boat speed. The N450 and ist predecessor N4.5 have a keel, no daggerboard to pivot around.
Turning into the tack not too abrubtly. Keep the jib out on the side of the previuous course as long as possible to pull the bows around. Only cleat it for the new course after the main flips over to the other side. The main should be sheeted in only slowly to pick up.
To get you on the right tack floating backwards, apply opposite rudder. This pushes the sterns in the direction you want rather than aiming the bows.
Good luck.