Having now tried it my first observation is that the alteration to the resulting sound from changing the power cord to the clock was greater than I intuitively anticipated.
So is the subjective result better with the fancy power cord into the DAC or clock? The answer is that the sound changes for both but not in the same aspects so there is no definitive answer.
In any case the answer has to be that as I now know that all dCS components are affected it is either necessary to change the cords for all of the boxes ( if the change is considered beneficial) or for none of them ( if the change is considered retrograde). Otherwise one is like a man with a car with four bald tyres who can only afford a single new one and is wondering which wheel to put it on.