I would say it is permissible. The examiner is assessing your ability to track yo and from the NDB using the displays in front of you. If you choose to adjust these displays to enhance your interpretation then good for you!
But.............
Beware! It's a given that you must keep the RBI in sync with your heading, which may not be easy to do on a bumpy day. Best advice probably is to work out a method that you really understand and which consistently delivers the accuracy that you need, then stick with that.
Good luck!