How to rank private school in Houston?

I have tried to find school for my children. I need a very good high school as my son is alredy 15 and has only more two years of high school in the USA before going to College. I have found the public school ranking in more that one site. I found SAT and ACT score for public schools but not for private schools. I'm looking for the performance of the students of Brittish School of Houston and the Village School. Does someone have more information to share about the SAT or ACT scores of those two schools?
thanks