Tubby was 3 - 4 months old and Peanut was 9-10 months old.

I think most places use 8 weeks as the youngest a kitten can be taken away from its mother. But I know with SAS and her new Juni Rose, the breeder wanted the kittens to stay much longer - wasn't it 14 weeks or something like that?

You're getting a kitten from a breeder sometime in August aren't you? I do know that it's best for the kitten if you have patience and not take it too soon. You'll end up with a much healthier, happier kitten, so although it's hard to be patient, in the long run you and she/he will be much better off.