Males can start breeding as small at 300grams but i start at 500 minimum before their ready.
Females i will start pairing in October at 1100-1200g and during winter they begin to eat like hogs while developing and end up around 1600+ before ovulation.
Do not push it with larger meals, just feed smaller prey items every 4-5 days rather larger meal every 7 days.
I feed males wean rats every 7 days and females small rats ever 5 days.