In case this thread is ever used for reference, there is a third way of loading up 120 and 220, found on many Rolleiflex TLRs and SLRs: there is a feeler roller to detect the beginning of the film. All you do is attach the end of the backing paper to the take-up spool after threading it under the feeler roller if necessary, check that it is on properly, and close the back. There is no lining up of arrows.