Hey Rob-F,
Basically you have three choices for developing tanks for 70mm (that I am aware of).
1) Kindermann 70mm Daylight Tank and 70mm stainless steel reel. This is what I was able to find after looking hard for a couple of years, I think I bought this one on German Ebay. B&H used to sell these new for $299 back in the seventies. They are around but don't come up all the time.
2) JOBO makes a 70mm reel that fits their tanks. I'm not that familar with it. But they are around.
3) Honeywell Nikor made a stainless steel tank and reel for 15' of film. Looks like a giant 35mm Nikor daylight tank. They are around.
Kindermann 70mm Tank & Reels by
Nokton48, on Flickr
My Kindermann 70mm Daylight tank & SS 70mm Kindermann Reel. To the left of it, is a X-Ray 70mm Plastic Reel for processing dental x-ray film. I found it on the internet, it was only like ten bucks new! Will not hold 15 feet, but will hold thirteen feet. TEN BUCKS!
Regarding loading, in the dark I load the spool was full as I can, without scratching the outside edges of the film, when I assemble everything. It's all done by touch. Scissors I keep in my back pocket, so I can find them!
😉