1. I listened to 4, posteriorly if it was just to listen (a non-respiratory complaint). I listened to 6 posteriorly + percussion, fremitus, etc. for a respiratory complaint. I could understand people adding 2 more posteriolaterally, and possibly 2 anteriorly.
2. Lolno. I listened to A and P for the heart only on every patient.
3. Long enough to hear the heart beat. You don't have to actually interpret the manuevers, you just have to show you can do them well. Same thing with any ophtho exams - Just make sure you use your right eye for pt's right eye (and vice-versa), take a glance in, and note the exam to be normal (b/c they're not going to have a pt with papiledema as a SP on CS).