800 is not advisable. I've always bred between 1300-1500 depending on the look of the snake, some of my gals have been thick but short so they don't weigh as much as the ones that are longer. All in all body condition is just as important as pure weight. I had one at 900 come to me gravid and she barely made it through and both eggs that made it through incubation were so deformed I had to euthanize them. I'm not saying a snake under a 1000 can't successfully breed, it's just not something I'd risk.
EDIT: most breeders (good ones) don't get a fast turn around on their hatchlings, that's why we have to wait years before some of the recessive genes become readily available.