By all means listen to your instructor, but I guess I don't understand why you aren't allowed to teach your dog to sit and stay.
The most problems I see with this exercise is the dogs move their feet, either to leave from the examiner - or into the person playing judge, for a butt scratch!
Friendly dogs and shy dogs are quickly sorted out.
In my novice class, I teach the stand for exam as performed in the AKC Novice regulations.
From a sit, the dog is lured to standing position. This luring motion becomes the command along with the verbal.
(I teach the stay using a platform in the puppy class and by Novice, the dogs know what stay means - in any position.)
The handler gives the dog the command and/or signal to stay and walks approximately 8 feet away and faces the dog.
The Judge approaches and touches the dog on the back of the neck/shoulders, back and/or croup - before stepping away and commands the handler to return to the dog.
The handler returns around the dog and moves up to heel position. The dog should not move at all during the entire exercise.
I have a video link to the moving stand for examination, and the rally stand-walk around your dog, if you'd like to see them.