Stereonet tricks, tips and intuition

So I have a midterm coming up for my structural geology class. The instructor is big on hand drawn stereo nets as they would be done in the field, no tracing paper no spinning things around just draw a circle and aproximate things.

For the most part I get how to use and calculate with the stereonet. Where i am having a problem is that we dont have a lot of time to do this and we are expected to (and need to) spend most of the time drawing cross sections and down plunge projections etc. The prof seems to think we should be able to answer several of the questions with out even looking at a stereo net and claims that all the "there wasnt enough time to do all this" comments are absurd. Although all the stereonet questions are multiple choice.

As an example we went over something today (please forgive me if the numbers are quite right, im going off memory)-

two limbs are oriented 060/25 and 354/33 what is their hinge line?

he immediately just goes well a,b,&d are wrong the answer must be C because its the only one whose plunge is less then the smallest dip of the two limbs!

we have no book and this guy is not very helpfull during office hours so I was hoping someone could point me in the direction of more time saving tricks like this....at this point i am not confident enough to even know for fact that the two limbs intersect haha.

like I said, for the most part I can make sense of the stereonet just really need to get some time savers down so I dont have to draw one everytime.



Thanks