I shall
repeat myself.
You should prepare the navigation in the way you were taught by your instructor (using whatever method was taught),
If your instructor says its fine - then go for it. As far as I know, how you work out your navigation isn't stipulated. How you work out your route before you fly isn't what the QXC is testing (thats what the nav exam is for). Its testing your ability to fly to your plan as you were taught and deal with a real world flight on your own.