You are not missing anything Zai. But would your rather conform to the expected centenary of all the other boats and drag like them in a blow? The professional answer, which I use when I know the depth
, is to buoy the second anchor. This marks the rough center of your expected radius, in the event of a change in direction of the boat.
However, notwithstanding all this anchor theory, it usually comes down to circumstances at the time, what type of hook you have, how much rode
, etc. It's called seamanship.