Quite the dissertation. I'd have to argue with the 80% power going backwards. That seems excessive to me unless your boat is way under powered. Some boats could drag their anchors around all day with 80% astern power.
You have also neglected to tell folks how they can tell if the anchor is set or dragging. It may not be apparent to some......evidently.
There is a tide in the affairs of men,
Which, taken at the flood, leads on to fortune;
Omitted, all the voyage of their life
Is bound in shallows and in miseries.
Shakespeare, Julius Caesar IV, iii, 217