n is for normal as you stated if it passes this area its a problem,
so long as your needle raises then the engine fan cuts in and the needle drops or a safe normal heat is indicated and maintained, there is no problem, ,
the water in header tank may bounce about a bit if you release the cap, if it overflows out the spout, its running too hot, otherwise its fine, just fill upto max when its cold, and do it up and keep aware of the needle position, it sounds fine,
, switch your fan on cold, go for a spin if it goes over the point of normal, sling your heater on hot and blowers on max , this always help lose a few centigrade, I think your fine