I recommend that you also ask if the district will qualify for the gifted classes with your outside testing. Some will, some won't.
Another thing to look at is intellectual peers. It sounds like that would be hard for EG son to find at Option A. It really makes a huge difference being in class with kids who "get it" than with kids who need repetition. And, your child is going to need other kids to challenge him and talk to him about stuff he wants to talk about.
Personally, I would jump at Option B. Meet with the gifted coordinator and show her/him your WPPSI testing and see if that would qualify him. Get a feel for the program. See how interested she is in having your son.
Please keep in mind that being gifted does not necessarily relate to being a high achiever. Many gifted kids are B students, not because they are not intellectually capable but because the work can slow them down or they don't see a point in doing it or it's something they master three years ago. In my experience, highly gifted kids (in general) don't care much about grades. High achievers do.
