Nothing like being prepared!
I have only been breeding for a couple of years, so haven't had to do too much worrying about rehoming yet. However over that time I have come to know my cats well and I know I have to rehome 2 girls and not keep them as pets. The reason being that these particular girls have behaviour problems. One is terrified of Bengals so has to be segregated, which is lonely for her. The other one is the opposite - large, and in charge and does beat the hell out of the other cats if she has a mind to. To keep those two on would be crazy. I love my big bully to bits and would love to keep her, but I have to think about my other cats too. These two need to go to homes where they can be 'only children'.
You'll find things crop up unexpectedly, fluffy, so you can't plan that far ahead - just have a general idea of what you are going to do, and your basic principles.