Hello Don,

Would you believe that I am not entirely happy with this 'the vertical height of the shafts was intended to equal one quarter of the Pyramid's intended height'.

My reason for viewing it with some caution is that it is the only instance (I'm lumping the four shafts together here) of Dimension A = Dimension B divided by 4 I have found in Khufu's pyramid.
Or, to be more accurate, it is the only instance I have found so far that does not have an alternative arithmetic and or geometric explanation.
Mind you, I've only recently noticed this close-to-70-royal-cubits factor so it is early days yet.

It would be interesting to know what, if anything, C. Wayne makes of it.

As for the length of the royal cubit used in Khufu's pyramid.
I theorise that the design of this pyramid's interior started with the floor plan of the King's Chamber (a simple 10rc by 20rc rectangle), so it is to this Chamber that I look for the length of the royal cubit used.
According to Petrie, the KC yields 20.632"/524mms, and I have found this measure to be consistently the best fit for my hypothesis on how the GP was designed.

Regards,

MJ