When should I take SAT IIs?

<p>I need some help deciding when to take my SAT IIs.</p>

<p>I'm for sure going to take Chemistry and Math 2C, but I also have AP Exams in May for Calc. and Chemistry.</p>

<p>Also, I was planning on retaking SAT Reasoning again in either May or June.</p>

<p>And another question if I'm not pushing it... Should I be taking a third SAT II test? I know that many colleges require only two, of which they pertain only to the major you're interested in. I took AP US last year... should probably cram and take it soon?</p>

<p>Thanks in advance!</p>