The cassette loading need not be a problem. I have used a 200' roll of FP4 cine-film with no accidents, though the same method can easily be used with any bulk 135 film.
The most practical arrangement I came up with was to put two small nails in a length of wood, 64" apart, then hook a perforation over one nail and pull to the other nail (right at the end of the wood strip) and hook the film over that too. I then stuck a piece of masking tape from the side of the reel over the perimeter 'edge', to stop the reel unwinding, and cut the film just after the nail. This gave a 36-exp. length of film which was then fixed to the cassette-core, using a piece of tape pre-cut for the job, and rolled up with the loose end of film still being held by the nail to avoid mad spirals of film flapping about. All of this in the dark, obviously.
The main thing is to be organised with the necessary bits and pieces, especially the bits of tape for the spool - and to avoid dropping the film(!). In practice it proceeds very smoothly after the first few rolls and you don't get the annoying piece of exposed film at the end of the roll, like you do with daylight-loaders.