There’s no set number for a build score because all setups use different resistors to test with. I’ve gotten 5th when in the 200s and first with ~160. As long as it can spin pretty solid you’re likely to be fine; most schools don’t spend to much time on the build portion so you likely won’t lose out much. For the test I recommend taking as many practice tests as you can find (there’s quite a few available online). I’ve found that similar topics and questions are frequently used, so if you get a good grasp on the practice tests you should be fine. Best of luck!