I would take September to feed them very well before introducing a male.
I offer at least 2 times a week if not 3 times a week, small rats to my big girls, and they are usually very willing to take the extra meals during this pre-breeding time.
Proof is in the pudding, no slugs from any female that eats really well during the feed up period.
I continue to feed up in October also, some/most of my big girls will take 10 to 12 meals a month during those 2 months.