You could make spools out of wood or something, and you could cover the red window, but the trouble would be determining when to stop winding. It's not obvious to me how you could solve this (it's basically the same problem we discussed earlier about using 220).
I don't know how much light would leak between the film gate and the pressure plate. I think you could fix that with strips of adhesive felt, but it would be inconvenient to remove so that you could shoot 120 again.
The price difference surprises me. Do you know anyone who travels to the States or western Europe who could bring back a few bricks of film?