Weight by itself cannot tell you whether a snake needs to eat more, back off, etc. in preparation for breeding season- you also have to look at the overall 'shape', for lack of a better term, of the snake. A breeding female that weighs, say, 1700 grams can be either fat or thin depending on the overall size of the snake. For example, I have a cinnamon pastel male I'm planning to breed this season. Currently he weighs about 650 grams. Even though that may seem light for a breeder male, I'm planning on backing off on his feeding before I breed him because, for his length, he's pretty chubby. On the other hand, I have a female pastel who is around the same weight, but is longer than he is, so she is actually slender for her length. I don't worry about overfeeding her, and offer her an extra meal every now and then. Snakes grow in different ways, just like people- some will grow long first and then fill out, some fill out and then take a while to get long. Rather than just looking at weight, try to look at each snake individually and feed accordingly in preparation for breeding.