I would never have guessed this! Are you going to rewind into the original cassette, or unload the takeup cassette and develop from there? I guess either will work.35mm cassettes are fitting to the cavities perfectly without moving.
It's not too far off from 6x14 (which is what people get out of converted Kodak 3A cameras on 120); it seems like it'll be a good panoramic ratio. You should post some photos of the setup; I bet other people would like to do this.24x60 will be funny.