The basics are only a guiding principle. Your strongest posture is the one that fits your constitution. That cannot be taught to you, you have to find it for yourself. It is not a question of widening your stance or narrowing it, if the truth be told. But, people will do what is comfortable for them, so if you allow them to, they will just make it up for themselves. That is why, you must always return to the basics. This is what is important.