the whiz wheel is a piece of cake once you get used to it. Do what i did when i was learning, i wrote on my E6B with a pen little hints with arrows pointing to --> fuel quantity here etc

It looked like junk but it helped me out. Dont try to master all of its functions because it is like trying to learn PI to 30 decimal places, just learn the functions you need to know and will be tested on. In the private ride I only had to use it for my groundspeed and estimated time of arrival to my new destination when we diverted.