Part of the problem I have with the discussion of where a Bong Sau should or shouldn't be placed is that it yields the thinker to an if/and mindset. In wing chun we learn the system only to eventually become free of the system, to allow fluidity and responsivness in any given situation. The process of combat is fast, furious and fluid, you dont have a game plan you simply respond to your oponant, you follow him, and use his tools against him. This means that your oponant can attack at any angle, any degree, and at any range of force, which only gives you the time to simply respond. There are thousands of possible responses in a given situation and it is up to you to neurologically resopond in a a nano second to what is happening. I find that the if/and mentality lacks this essentialo fluidity, and freezes your mind at crucial moments, which is why I said earlier, if you need it high then do it high, if you need it low then do it low, wherever you need it do it.