70mm is KEWL
I have about twenty-five 100' and 150' rolls of 70mm Type II perforated film, in a wide range of Kodak and Agfa B&W and color emulsions, in my deep-freeze. Most of these are aerial films I have bought on Ebay. Number of exposures possible varies, depending on the thinness of the film stock. I have some Plus-X Aerorecon film, which is incredibly thin, I can load over 250 exposures in a cartridge with that stuff, although the A70 film counter only goes to 80.
I develop the film in a 70mm Kindermann daylight tank, with stainless steel reel, and lighttight plastic tub with lighttight lid. I also have a white plastic 70mm film reel that I bought for $8 US from a Medical X-Ray company in Texas. After washing, I photo-flo, and cut the 70mm film into strips of twelve, and hang them on closepins to dry.
Then cut into strips of four, and into a Vue-All 70mm page. 8.5x11" paper is required for proof-printing, as the strips of 70mm film are quite wide.
70mm is Kewl, it's like shooting digital, without the chimping. I seldom look at the film counter, nor run out of film, during something exciting. My favorite 70mm emulsion (without question) is Kodak Surveillance Film. It is 400EI, and looks like old Tri-X. I bought half a carton of it (15-150' rolls) from a military surplus place out in California.
I would love to find a Hasselblad A500 Magazine in good condition. That takes 100' at a time, and plugs into the EL/M. I do have 100' 70mm Nikor reels and tanks in my darkroom, in fact, I have three of them!