PB: Yes, this was another thing I was going to mention, what parameters one can reasonably expect when trying to make such an alignment with naked-eye observation. I had figured you had looked into that.
I checked this naked eye observation of the Belt Stars myself whilst at Giza a number of years ago. With a very rudimentary device made of wood, string and beads I could observe and record the Orion Belt asterism to a very high degree of accuracy - higher indeed than what we find in the Gizamid 'asterism'.
This suggests to me that the middle pyramid (G2) was deliberately offset from its true Belt ground location. Why do I say this? Well the proof of this is, imo, presented to us in the Gizamids. Consider:
1) The Giza Plateau Pyramids
In the 1980s, American Egyptologist, Dr Mark Lehner (whilst working with Dr Hans Goedicke at Giza) observed what came to be known as the Great Giza Diagonal or the 'Lehner-Goedicke Line'. You can see this in the image below:
2) The Lehner-Goedicke Line
The Lehner-Goedicke Line is a theoretical line that passes through the diagonal of G1a, touches the SE corner of G1, misses the SE corner of G2 by around 20 feet or so, touches the SE corner of G3 and passes through the diagonal of G3a. Egyptologists have tried to explain this arrangement by suggesting an alignment to Heliopolis (not one that I buy into). This 'plan' clearly raises the question as to why G2 is offset from this line.
But the plan is much more nuanced than just this line and actually presents 2 further significant lines that Dr Lehner and Dr Goedicke missed and these are lines that, imo, tell us unequivocally that Giza was formed as a single, homogeneous, unified design.
3) The Giza Pyramid 'Inter-Quarter Lines'
As you can see in the image above, there is a clear geometric relationship between the dimensions of G1 and G3 while G2 is somewhat off this plan indicating (again imo), that G2, when being built, was offset slightly from the planned position. If G1 or G3 were in slightly different locations on the plateau, this geometric correlation we observe here simply would not 'work'.
So, what was the underlying plan - the 'design template' - for this geometric relationship? Simple - Orion's Belt. Let's now overlay Orion's Belt over G1 and G3 (red dots):
4) Orion's Belt with G1-G3 Fulcrum
As you can see, G2 is some way off the middle Belt star, Al Nilam. And, as we know from above, it is also offset some way from the Inter-Quarter lines, suggesting again that G2 was, for whatever reason, moved slightly off plan when building actually commenced. But wait - what would happen to the inter-quarter lines if we centered G2 on Al Nilam i.e. if we moved G2 to its (theoretical) original planned position? Well, let's see:
5) G2 Centered on Al Nilam
And it all falls into place. As you can now see, G2 'conforms' and locks into the inter-quarter lines along with G1 and G3. This to me is compelling evidence that Giza was:
a) Designed as a unified plan
b) Its underlying design template was Orion's Belt
c) G2 was, for whatever reason, moved slightly off plan when building commenced.
I suggest that G2 had to be moved slightly off plan in order to create a specific angle (i.e. date) to intersect the Giza Precession Timeline to the fixed body of rock we call the Sphinx, thus:
Were G2 to have remained in its original Belt ground position then it would have created a different G2-Sphinx angle and thus a different intersection point (date) on the Giza Precession Timeline.