“I'm still thinking about the reason for the slopeing side, the ancients never did anything without a reason.”
“We must find out the profile of the holes for the Trilithon, whatever the holes say is OK by me.”

I’ve tried, but it’s got me beat. Let’s hope someone on TMA can help. Failing that, if Four Winds managed to get Mr Burl interested we could go on his opinion.
I’d love to think there was a chance that there’s enough evidence to at least indicate a “most likely” method, based particularly on how much room they had.
But what if the evidence and/or Mr Burl suggested “large numbers hauling up” was more likely? Would you want to switch to that? Your method is always going to remain a possibility, so demonstrating it will remain a valid option. So it would come down to your personal preference as to what you wanted to do.