It's not the advice you are going to want to hear, but I would take a step back if I were you and consider why you want to breed and what you are going to do with the babies if you don't sell them.
Getting snakes up to size is only half of the battle, even if you get them up to size by this fall or even next fall that is no guarantee that they will take for you. You can feed smaller meals every 4-5days to get more weight on them quicker and your male will breed at a much smaller size than your female, but again size isn't everything.
Use the time while they are getting up to size to make sure you have thought everything through. This is my first season, I have been pairing my snakes since late October and I haven't seen any signs that my girls are even close to ovulating yet. It takes a lot of patience to breed ball pythons and getting them up to size is the first test of that.