Hi Nigel
Nice to hear from you again. Seems to me though that you fail to appriciate the problems of dragging really heavy stones on rollers.
Before our experiments it was known that stones up to 10 tons could be moved on successfully using rollers. We now know that stones weighing up to 12 tons can also be moved this way. The question is how far per day? How far could a team move such a stone before they became totally knackered? Believe me had you been part of the pulling team that day you would begin to appriciate the problem.
Furthermore when using rollers the problem increases expotentialy with the wieght of the stone. With stone-rowing it does not.