Gizamid dimensions are based on the Greek foot. But there were different feet in ancient Hellas at different times.
The one used was the Parthenon foot or photon foot. Some metrologists call it the geographic foot.
1 photon foot = 0.308803 meters = 12.1576 inches
100 photon feet = width of Parthenon at the stylobate
The base lengths of the three pyramids expresses in photon feet (f) are as follows:
Khufu = 746 f
OGYGOS = 70 + 3 + 400 + 3 + 70 + 200 = 746
Kafre = 697 f
Menkaure = 342 f
The average is an integer value:
avg = 595 f = 5 x 119 f
SEIRIOS(Sirius) = 200 + 5 + 10 + 100 + 10 + 70 + 200 = 595
Now for the height. The values are:
Khufu = 475 f
Kafre = 465 f
Menkaure = 212 f
Once again a strong indication this is the correct plan is that the average value being integer:
avg = 384 f
With this average value we can compute a corresponding average slope. This is:
phi = atan(384/[595/2]) = 52.2336°
But the G1-G3-east angle(complementary to the G3-G1 azimuth) is:
z = 52.224°
If anybody believes the survey data agree better with a different length measure I am all ears.