Questioning the Cross section methods

As I was altering the methods for the Cross-sectional non-photo method for the "Big Field Day" I can't seem to figure out if there is any advantage/any difference in setting up two poles along each bank versus just setting up one that runs down the center of the bank. I'm sort of leaning towards the idea that either will give the same results and in that case it would be a lot less work to just set up the one section of poles. Also, does it matter if the poles are straight?? For some reason I'm just questioning how we will be getting accurate data without knowing the location of the poles, but I may have just thought about it for too long....