tmybr
"I know that in pre-flight planning I must use a whiz wheel"
I would hope that you will learn to do your planning without a Wizz Wheel. The wizz wheel is a tool that allows you to be a little more accurate however, you can and will make mistakes with it! that means that you have to do a mental cross check.
If you are capable of checking it, you can also obtain the results by the same process, negating the wheel entirely.
If a student on a diversion produced one I think I would confiscate it; as an examiner I want to see a diversion conducted without it.
From a safety perspective, using a wizz wheel in the air, single pilot, is on a par with driving down the fast lane of the M1 sending text messages on a hand held phone!