Re: When do you teach your personal style?
I remember when I first started teaching, one piece of advice I got from a sempai was to teach whatever I know best myself. A second piece was to keep it basic (partly because of my juniorness but doubly so because the class I was teaching was a Basics class).
In practice I found that this tends to mean you focus on what feel to you to be basic things, that you yourself have spent the most hours learning and that will likewise be most helpful to your students, but also that different people will naturally have certain things come up more or less often in their class. Which seems to me fine.
For me when I think of personal style, though, I tend to think of the differences we all have that are relatively unconscious, or that just happen, due to differences in body and personality. I wouldn't deliberately try to teach something that actually contradicted my Sensei's teaching - I don't have any particular desire to, but even if I did, it's ultimately his dojo and people have joined it because they want to study his style, not mine or someone else's.
But that doesn't mean everyone's class looks the same, either. There are a number of senior students who teach at my dojo, and all are distinctive. We all have favourite exercises we do more often, different ways of explaining things, different techniques or different variations of the same technique we teach a bit more often or a lot more often, even different warm ups. And we all do the same technique somewhat differently simply because we're all different people.
The differences come through to the students, even without a deliberate effort to 'be unique'.