I also believe that G3 is quite significant, and that G1 and G2 certainly have their own importance, but also there is another factor involved. The entrance of G1 has a rather curious scene depicted above it, which was once hidden by surrounding blocks and casing stones. Now, the scene is open to the world and roofed over by one pair of very large blocks, where before it had three or four pairs.
What is depicted?
The lower section has two mounds and a definite geometric shape; the upper section is the negative space of a pyramid. When hidden, was it a talisman for the pyramid, or a talisman for the people who knew it was there? Either way, it is a very important inclusion in the 'language' of the pyramids.
All the best to you both !