I agree with dave99ag.
I ran CC & track in HS, and we were told to go with what was comfortable. It is like running stride, everybody has a different form they use, and what is good for one isn't necessarily good for someone else.
I teach my kids to do what they are comfortable with. Of course, if your coach says one thing, you best do what he says, or you might not be running for him.
"It takes a man to be a father....."