Don't look at school ratings to find the right match. High ratings also attract high achievers. We've been quite fond of our partial gifted magnet because the parents sending their kids to the magnet program despite the school numbers seem to have a genuine interest in appropriate challenges. The school is also quite open and flexible and motivated.
Be sure to keeep your kid(s) in the loop.
Come right out of the gate with particular common gifted challeneges (like overexcitabilities) and hope for responses like: of course that's common with gifted kids.