Thanks MrDave. I think you will do just fine.
Beyond what Kneale suggested, remember to always describe what it feels like to you when describing the tasks, along with a simple the explanation of the expected pressure changes and ski/snow interaction. Follow through with some good feedback and coaching and you should get some good changes in the group.
You could take the pull back into a more delayed weight transfer through the top of the turn, with the idea that the turn will be entered with more equal weight on both feet, with a more natural transfer through middle of the turn. This can be done with easy open parallel turns as well, instead of the more traditional use of delayed weight transfer in more dynamic parallel turns.
I've always liked "cowboy turns" for developing inside foot and leg activity and more fluid long leg short leg movements, along with effective ski/snow interaction with both skis.
If I could offer any advice it would be to teach what you know and not to try to use something someone told you the night before without successfull practice. We need ownership of what we teach, particularly in an exam setting. You probably know that already though. Let us know how it goes for you, and if we can help in any further way.