Okay, so it is possible to handle a 400 foot spool while loading cassettes manually. I envisioned a small hell trying to keep the film taught to keep the big spool from unwinding (does such a huge amount of film do that?) while trying to cut off a suitable amount for one roll. My plan for using the 100 ft spools was to limit the times I'd have to handle the 400 ft spool to 4 times, and then being able to use a normal bulk loader. It would even allow me to make several pre-rolled 100 ft spools, so with 4 100 ft spools and 4 containers I could actually get rid of the whole big spool in one sitting. But getting spools and containers is the catch, I don't want to have to use up 400 ft of some other film before I can start using the motion picture stock.

BTW, does anybody have the dimensions for the "hole" in the middle of 400 ft and 100 ft spools? I'm planning on making a small "machine" in which I can load the 2 spools and then just crank on a handle to load the smaller spool.
And are there any difference in the cores that bulkloaders take? Some seem to just take a cardboard tube with film wound on it.