Also I would think the 70mm would have more issues with IR light leak than normal film... But I could be wrong.
I would also suspect the prying open of the cassette would cause light leak issues and defeat the purpose of the felt when you want to change a roll out of the back in daylight.
I haven't had any issues now that I've labeled the direction and stuck to that. But I started with never used cassettes so I started ahead of the game.
I get frustrated with 70mm, I've considered selling the lot... And moving on, and then of course I just bought a graflock 70mm back for a 4x5 so now I'm all in... :shrug:
Mamiya: 7 II, RZ67 Pro II / Canon: 1V, AE-1, 5DmkII / Kodak: No 1 Pocket Autographic, No 1A Pocket Autographic | Sent w/ iPhone using Tapatalk