hi tin! i'll tell you what i know about roasting a duck. surprise, its not all that much. my credentials as a foodie come more from appreciating good food than preparing it.
the best frozen ducklings i've had come from long island. living in virginia, my ducks are now raised in south carolina. never had a bad experience with a frozen duck. not an appreciable difference in buying a fresh one from what i could tell. frank z.'s duck site is excellent!! that jessie is a girl after my own heart when it comes to ducks and duck fat. i have never done the scoring or flipping the bird from side to side, but probably all sound advice. the orange packets that come with the bird get tossed in my house, but jessie's sauce recipe looks good. i usually stuff my bird with an apple and onion, but it's pretty tight quarters in there with little room. i make stuffing on the side. your duckling should serve four to six people, but don't expect much in the way of leftovers. my last two ducks rendered little fat--about 1/3 i had come to expect. then, soon after, i learned that much of the (coveted) fat has been bred out of the duck in recent years! fools!!! to me, the duck fat is almost as important as the duck's crispy brown skin and its moist dark muscled meat. it's really hard to go too far wrong cooking a duck. i've never messed one up yet!
good luck with your bird. my guess is it won't be your last....