The fun with it is the height of the pillar, with its glistening ben-ben stone atop reflecting the sun for as far as it could be seen, and how high something at Giza would have to be in order to see that reflection as but a glimmer right on the horizon...right on it, mind you...right at that perfect spot where, just a few inches further back would make it disappear.
One could imagine that if one were atop another certain construction at Giza, viewing exactly 8 nm due north, one could see something else, not as high as the Heliopolis pillar but a smaller height, that would have a reflection of the sun right upon the horizon, where just a few inches south would have that reflection disappear. One could very well imagine that 8 nm was perfectly known.
If one knew what 8 nm was, in relation to the size of Earth which is based upon degrees, then one could try to estimate how high the land was above the water level at the time, and have a clear estimation of the size of Earth according to...what? Average land height? Entire water level? Something based upon the two?
That offers up a time period when the water level was ‘so high’ and the land was always the same height, which may indicate the exact time period when exacting measures offer up the RC and everything else that goes with it. It may not come down to getting a better RC measure but a better water level to work from...if the Heliopolis pillar and Giza and something else 8 nm away have anything to do with it.
It adds in and correlates with other measures obtained by latitudes of distant locations and what the sun is doing in casting/not casting shadows.
Well, just a thought