FWIW, my DH is 6'8" and I'm 5'6" but our DD was only 6lb6oz (2.89kg) born and 19inches so 0000's were huge on her for about 4 weeks. The good thing with the bonds growsuits is that they stretch so you can usually get a little bit more time in them. also, if their feet are too big but their body is OK, just cut the toes out and put socks on bub's feet. A GF of mine had to do that with her DS. As for how long their in their sizing, it depends on where you shop. Big W tends to be on the small side whereas Best&Less, the larger size. My DD would grow quite rapidly and was basically in a new size setting every 3 months or so. Now, she's always a size or 2 larger than her age.

I don't know if that's helpful or not.