I have a 70mm Hassleblad back and a couple long rolls of 70mm Kodak Tech Pan. I found a Kindermann 70mm SS reel and I now develop the film with that.
Before I found the Kindermann 70mm reel, I hacked a couple 70mm reels out of some plastic 120 roll film reel components. The hacked reels worked ok for processing short lengths of 70mm film.
I recently acquired a 70mm rb back - intending to fit it to the 2.25x3.25 Graflock on my Century Graphic.