<p>If a school requires three SAT subject tests (or recommends) two in the general field that you are intended in eventually majoring in (humanities or math/sci) will be sufficient. </p>
<p>SAT IIs don’t require advanced knowledge like the APs to get good scores. I found prepping for them extremely difficult and boring and in the end, unhelpful. I would just take a practice test for each subject that I’m considering and then just concentrate on the two or three best subjects (they should be in your intended field anyway, or why would you be interested in that field)</p>