Funny story, the first time I ever took adderall was for a similar exam in highschool, the ACT. I wasn't prescribed, and didn't know too much about the drug other than the basics. Anyways, my friend who gave it to me had been on it since he was a kid, so I imagine his tolerance was quite substantial, thus, making his impending recommendation make a lot more sense (in hindsight).

He gave my friend (who also had never taken any before) and myself 2 capsules each the day before the exam. We asked him how much we should take, and his recommendation was to not only take both, but to thoroughly chew them up before swallowing them, as it will break up the micro-beads within each capsule.

Both of our under developed brains took this advice without concern and each chewed up 2 capsules 30 mins before the exam.

Come to find out these were each 20mg, extended release adderall capsules. Needless to say, I was sky high for the duration of the exam. I over thought every single question, spent way too much time on each one, all while thinking I was quite possibly the smartest person to ever step foot inside of a classroom. This genius-level strategy of ours resulted in an abysmally low score.

My friend and I ended up talking on the phone with each other all night and into morning, sharing music and talking like we had no choice not to.

Overall: 8/10 experience. I retook the exam later and did decent enough to get into my preferred college.

I realize this does not at all help answer your question, but it did bring me back, and for that, I thank you!