It's not length you have to focus on; it's weight (and age). And also, just because a female is 1500 grams doesn't mean she can produce a viable clutch. If she is 38" and 1500 grams, that's great. If she is 50" and 1500 grams, she's way too slim (imo, anyway). As far as age goes, a male can be 9 months old, and 1,000 grams, but not be producing sperm yet.
Just something else to think about.
Jennifer