“Would it be possible to place a basket/box in the centre of the rope and slowly load it with smaller stones? Would this allow a controlled lift?”
Christ! Now we’re REALLY motoring!
In theory, one bloke could do the whole lift, given time.
Add to this, Gordon’s idea of people levering the stone forward by pulling on ropes attached to levers ( or could those ropes too have boxes placed on them ?*!!!!… )