Every school has different policies when it comes to the SSAT–and, on top of that, the SSAT requirements will differ from year to year, and they’ll also depend on your race, gender, and background.
So the short answer is that there’s no real way to know what score your school requires.
If you really want to know what kind of score your dream school is looking for, the best thing you can do is call the school’s admissions office, describe your situation, and ask them directly what kinds of scores they consider to be competitive for a person like you.
Doing anything else–asking people on forums, talking to someone who went to the school, or looking around online–is ultimately just speculation, and a waste of your time. For this kind of information, it is always best just to pick up the phone and go to the source. Then, you’ll have real, concrete information you can work with instead of someone’s best guess.
Of course, as a general rule, a higher test score is always better!