We take steps to ensure all the dojo in our organization have consistent kihon versions of techniques. We do this via instructors meeting every other month and an instructors seminar once a year.
Which I think is a great idea, but it doesn't really answer the question. One's "personal style" is not going to be kihon, by definition.
I would never teach variations to brand new beginners, unless it was to explain the reason for a particular movement. But a class full of black and brown belts is probably ready to start thinking about how many different versions can still be "ikkyo."