I am doing the same test on Friday as well, but in Clinton, and I have no idea where we are riding, but if you read in the back of your book it looks like they basically make you go around the block and they stand on the corner and watch you, when I went to write my M1 the MTO chick joked with me saying that if I am going to drop my bike on the exit test do it on one of the back roads where they can't see me. lol
If you are comfortable you will be fine i am sure, but the 50% for the serpentine...are you dragging your rear brake? Best if you don't put your foot down at all. Good luck and let us know how you do and I will do the same.