Its hard to put a number on full grown. There is a post in the advanced husbandry forum where a 900g female laid eggs. I believe it was a fairly old snake that was wild caught and wouldn't put on any more weight so I guess you could say it was full grown. And then at the other end of the scale there are 5000g females..
edit: Just to note I wouldn't recommend breeding anything under 1500. However there are special circumstances..