The bracing struts are not a problem; they can be anchored into sockets in the ground. I thought you were intending to use the lintel as an anchor for the ropes.

But anyway, if you are relying on ropes to take the strain of the levers, then you are using ropes. So yes, we do need ropes.

Why go to all the trouble with the tower when ropes can be used directly to raise the stone?