Along with my stash of 10 70mm film reels, I have a couple 116 film developing aprons. Using them with modern day tanks works out very well.
You can get odd sized film aprons from old Kodacraft film developing tanks. Easily found on ebay for $10. Other sizes were made.
There is a seller selling new 35mm film aprons on ebay, calling them "film lasagna". Maybe he could do a 70mm version?
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