Ball pythons do not brumate. The breeding season is a pretty wide range actually. Usually starting sometime between Oct and July. In captivity of course. There is no need to have a cooling period. It's no requirement. Just personal preferences. Size and age is what determines the size of the clutch. Older larger females will produce larger clutches. Normally.
Everyone has their own system. We for instance do not use belly heat. We use room ambient temps. We have started to maternal incubate last year. The incubator is now only used for emergencies. Female snakes can and do eat on eggs.
Your ball pythons will not breed when you want them to. Only when they are ready. When you stick a male in a tub with a female and she starts tail wagging and peeing all over the place..... you know she is willing, ready and able!