I used to fiddle around with old Kodak and other 620 rollfilm cameras. When the new film supply came to an end I learned from a magazine or somewhere that the plastic spools of Kodak film (at that time, anyway) could be trimmed with really tough scissors. There was even a groove in the spools which was a cutting guide. So, look at your 120 film and check this out. In a pinch I have even had to use an old 120 spool to make a take-up spool for the 620 camera. Any black and white or color film could be used as long as it was no faster than 125 speed or it would over expose in the non-adjustable cameras.

     The 620 spools used to be metal and the 120 spools were plastic. Foreign 120 spools did not have the groove and were not usable. They did have a raised bead around the outside edge of each end of the spool but were harder to cut.

     If this is all garbage now, let me know. I moved from a place to a wet darkroom in 1985 and got rid of my enlarger and so on. My professional 120 cameras followed soon after and I gave away a couple of hundred rolls of film after reality kicked in. I had it in the freezer but it was out of date. So, I haven't used 120 film for many years.

    Good luck with this. Maybe it will still work.