Hi Polyglot, On my picture, plastic core is only for illustration, since my 70mm reel still lives in the dark. You are right, the bolt is holding my film reel. I'm holding film spool in my hands and just roll it. On the end I insert spool into cassette.
I loaded Double-X Aerographic film 2405 to film back on the room light and had severe light leaks. From now on I'm doing it in total darkness. 2405 is with "ivory" colour backing and transmitted light a lot. I'm cinematographer by training and dealt a lot with daylight loading of 16mm film on 100' rolls and never seen such leaks. Yes, with Hasselblad back you also had to wind a few frames after loading the 70mm back. When I reached the end of film i unloaded it from the magazine and had light leaks from that end too. One fine lesson in handling 70mm film! Just rolled 2 cassettes today and loaded one all the way to magazine in the dark.