If you have a way of lifting the rocks and setting them atop each other, you can use the method. Just use a lighter "proxy" rock to bang on the heavier one, test fit, bang on the high spots, test fit, bang on the high spots, test fit, etc., until it is as accurate as you like.
There also turn out to be sites where this work was in progress when it was abandoned.
So feel free to believe in space aliens if you like :-) I subscribe to the notion that the simplest explanation is the most likely.
* So feel free to believe in space aliens if you like :-)
Boring straw-man. I was refuting the fact that this could have been done in 30 minutes with rocks of that size. Nobody is suggesting the existence of extra-terrestrials, (other than you).
It was demonstrated on TV with rocks about a cubic foot in size. Many Inca walls are built with stones that size. The technique is adaptable to larger stones, but of course they'll take longer.
Remind me how much the rocks weighed?