For proper rotation and production you need to have one female rat per snake, otherwise you will not produce consitantly.

I do not recommend leaving the male in back to back litter takes it's toll very fast on the females, they are pregnant while nursing the litters will get smaller and so will the babies.

Setup 3 tubs with females and rotate your male spending 2 weeks at the time in each tub, that's the best solution in your case.

I also recommend to switch a few animals on f/t to take care of the surplus, rats grow fast and when they are larger than you need just euthanize and freeze them.