For me it's based on the female to some degree. If she is something that I plan on having for several seasons the answer is always to breed her 3rd winter (~2.5 years) and over 1500g (hopefully 2000g).
If it's something that I'm only using for a season or two the answer would be 1200g minimum for a female 3 winters old or older, 1500g minimum for a female under 3 winters old.
I'm with Colin. 1000g wall sucks....and happens too often on fun projects!
Hope that helps.![]()