If we ever get to meet in the future...I owe you a cigar. I agree with you on this:
"BTW, this is not the only example of partial trenching of blocks in a quarry."
So we at least know that the enclosure of the Khafra Pyramid was also a quarry. This is important since from this we can deduct what direction the megalith blocks were hauled,...giving us a better idea what the ramp would have looked like.
But I disagree with Klemm,..since these stones would obviously have been used in building of the first 10 courses of the Great Pyramid,...but probably in the inner core of the great structure which would have to uphold an extreme stress of weight.
This is very important for my research,...since it explains that the Pyramid builders were not idiots,...like you know who,...and haul great weights against gravity. Archea your a smart person,..I do beleive you know what I mean.
If my reasearch is right,..then that would mean that the two great pyramids were built together.