If you”re not going to take Subject Tests, then you can remove some schools from your list. That’s step one in the decision tree.
There’s not really any score that’s “good enough”. Every 10 points will improve your application a little bit, but in the context of many data points that go into the decision. Plenty of 1600 and 36 students are declined each year. Once you’re at the 75th percentile for a given school, the incremental benefit of a higher score gets smaller and smaller.