Wow. Given the gearing that’s involved the drive train must have been made really well with negligible friction. Mine has always required significant input to turn even when new over a decade ago. Presumably the handle doesn’t fall to the bottom from both east and west positions as suggested in your first post? (I can imagine it feasible the weight of the deck could turn the handle one way, but no way can I imagine the weight of the handle could raise the deck, which is what is required for the handle to fall in the other direction). I’ll take a look at the underside of mine later today to remind myself what takes up the chain tension, but I think the chain has a lot of slack in it anyway on mine without issues.
if you set it up to fall, can you put a stick though that you know top and bottom were parallel to start with, and what the difference is per metre after you have fed it through?
Stuart