AI - I don't think you fully listened to their story. For a start, when they say they descended to an estimated 100' AGL, that is exactly what they meant. Yes, it is only 4mb worth of altitude - assuming a flat earth. But the point they were making is that they painted themselves into a corner. They could either descend through cloud in daylight or descend at night, maybe engine out - they chose the former. The important thing they admitted to is that they ran out of options because of poor decision making in the first place. And dead reckoning is just that. An educated guess. I've done quite a few trips like that 'down-under' and I can tell you it works. But overall, we can all now learn from their mistakes. What is a shame is that their initial flying education was so poor. Some vital things were omitted.
PM