I would draw one reference line at 10 degrees to about halfway along the track. This will give you something to judge how far off track you are, if it's the side you didn't draw the line you can still judge it from one line.
Drawing four fan lines in a kite shape is rather excessive, but I see a lot of other instructors teaching to do this for every single leg. In my experience, one line is enough for any leg and just gives a reference to make a calculated correction. Otherwise, come test you're left saying "I'm off track, so will turn 10 degrees to the left" and if the examiner quizzes you on where that figure came from it seems rather plucked from the air. It is better to have a method to fall back on at least for test, then you can do whatever you want once you pass.