Thanks for the correction Beagle. However my point was that these people were the very best around; the best selected, best trained, and far more current than anybody in GA.
Today, there is no need to do stuff like this. The equipment and methods exist to plan a flight and execute it accurately and predictably. And if the MPG does drop (e.g. a massive unexpected headwind) then you will be able to divert early.
So much of what we fly with and how we fly is still hanging on 1940s 1950s 1960s practices. I've just done the JAA IR conversion, on which about 90% of the time was spent doing NDB holds and approaches, which almost nobody does (using the ADF) nowadays. Translate that to a typical 55hr ME IR and multiply it by the # of FTO ATPL students and add up the cost... for exactly what purpose?