I've got a 1200g female that I feel is too small to breed. Some say 1000g is the magic number, and others say don't do it till she hits at least 1500g...I am going to stick with 1500g+

Breeding is not something you want to jump into. If your biggest girl is 1200 grams, then IMO you should wait till next year to fatten her up a bit more.