It seems to be pretty straight forward, concept-wise. It's just a lot of work to get them lowered by hand. Mark Allen jammed an object, like a hammer, under that lever in the first picture to hold it in place.
I thought that we had a placard posted in the FTR on how to do hand-rigging, but I couldn't even see where one used to be posted. Makes me wonder if Batfish ever had one. They probably just taught everyone word of mouth back in the day.