With 70mm perforated film I just cut our perforation and use regular 120 sleeves. Without perforation as guide, cutting is harder. Ask here Nokton48 or on this thread at RFF. Good luck finding it!
Unperforated 70mm film is great for making 616/116 if you have original backing paper and spindles. Must be fun using that old camera? I did roll perforated film and produced this. I can not remember how did I store those negatives? Most likely I cut individual frames and used 4x5 sleeves? Very wasteful!