It sounds like a great plan. Technically you should weigh the food when defrosted, but with a quality product there shouldn't be much water/ice so it should be about the same. Also no need to be too precise with a puppy, just feed by eye, if she starts getting podgy cut back a little.
Chicken wing tips are very handy as they will add enough bone to counteract a soft bowel movement. So keep an eye on her poo, if it gets too firm or chalky you should avoid any more wing tips for a while. Natural Instinct is quite bone heavy, so you might need to feed some plain meat as well. Keep an eye on her poos, they are the best indication of what she needs.