From my experience, i was able to adapt to any question thrown at me (maybe i got a bit lucky with the questions given). However to be on the safe side, once you memorised your essay make sure you practice writing it to different questions. Normally I would suggest you to practice writing to different questions and showing to your teacher, however, knowing that you only got a few days before your exam i wouldn't bother showing it to your teacher. Just make sure when you walk into the exam, you are prepared to throw out some of the techniques and include your back up techniques, and link your techniques to different themes in order to address the question (please make sure you can do this, i can't stress how important this is!).
And one more thing, i wouldn't be too caught up about being rank 1, as long as your in the top 3 you are still highly capable of scoring a band 6!
Anyway I wish you the best of luck in your exams!
Pls update me on how well you did in your english exam