When Butler entered the scene two decades ago his proposal for a cubit shorter than Petrie's appeared to be backed up by the correspondence between chamber sizes and pyramid layout (at the same time producing the same fibonacci terms as found in Khufu). But this scheme is discrepant wrt to Petrie's. Does this mean the builders 'fudged' things in order to fit these different schemes together?

We tend to argue over minutiae but are we missing the big picture? In the diagram above there are four arcs (centred on the middle and northeast corner of Khufu, and the southwest and northwest corners of Menkaure). Those arcs meeting at the northeast corner of Khafre are quite precise whereas those meeting at the southwest corner of Khafre are less so. Yet they are obviously intentional.

This diagram is virtually symmetrical - bounded by the east side of Khufu and the west side of Menkaure, and the south side of Khufu and the north side of Menkaure. The diagonal through Khafre points to Heliopolis.

Can it be that the designers of Giza were more sophisticated than scholars will admit?