I would counsel to consider the size of the boarding population rather than the percent alone as well as where kids are from. There are schools where lots of kids leave for the weekend.
But at this point for you, I would think about what you would like the school to offer. It’s often hard to pick up on the vibe, but there are schools that might feel more comfortable for athletes/artists/URM/students with FA. So you can work your way through that too.
Take a look at Peddie, George, Westtown, Hill, Blair as well as those mentioned upthread. Overall, these Mid-Atlantic schools are a bit less competitive. They have very different vibes, but sometimes, looking at a variety of options can help clarify what you want and what you don’t.