I had a 70mm reel, but plastic, large Jobo tank with a huge reel for developing Hasselblad back, 70mm (cassette) films.
It was a good tool, but this was in the early/mid 1980's and I loved everything photographic, so loading it was no something I took note of.
Loaded and filled, it was a bit of a handful, but it was more difficult to complete shooting those large rolls of film often enough, to become 'expert' with the handling of it all.
I ended up just shooting colour negative film, and letting a lab develope them, when finally completed, and 120 for everything else, so I could get back E6 colour slides in a few hours and do the black and white myself.
If the hight is correct on that large steel tank, for the 70mm stuff you've shot, go for it, but use wide duct tape to join the top and tank, because you'll want them to stay together, should that heavy, wet tank, take a fall.
You might also want a wide enough board to catch a falling tank, if your sink is ABS or other plastic, just in case.
IMO.