How often are you going to be breeding here?
Putting two females in at one time will give you any where from 18-32 rats in one go. Your feeding pinks right? That's 9 to 16 weeks of food right there for your 2 snakes, or you could plan ahead, freeze say 5 weeks worth of pinks, and then a week later freeze the rest at the chubb size.
Your not going to need to breed them a lot for only 2 snakes.
Even if you do plan on getting a few more snakes, then you will be increasing your production margin by just putting those two females back in with males more often.
If you really want to just jump right in with a bunch of rats, that's fine I guess, I just don't see the need for it with only 2 snakes taking mice pinks.
Females don't need to be rotated like you want to do. You can successfully breed those same rats for over a year. Then, when you feel you need replacements, you hold back 2 new females.
I guess I'm just trying to save you some time and money here. Raising rats for 2 snakes shouldnt be so intense like your talking about.
BTW, I usually say 2.2, because no rat is ever alone by themselves, which is just cruel to do to them. They need to have a partner at all times, being the highly social animal they are.