Re: When do you teach your personal style?
If you do have a principle based curriculum, then you should always teach to that curriculum and avoid personal "style" preferences most of the time.
If you don't have a principle based curriculum, you will be teaching your own "style" right from the beginning. Your style will be influenced by your teacher, your training partners, and what you find works for you when you train.
In my experience, many (most?) dojo or groups don't have a principle based curriculum, they have a technique based curriculum.