I had the WORST time with 120 on a plastic reel. In the end I had to give it up and turn it over to my husband (and was in a rotten mood for the rest of the day, because now I'm freaked out by it).
We had run a test roll through an old Kodak A1 to check for light leaks in the bellows. I wanted to develop it at home. I sat and practiced on an exposed roll of Konica IR, using my changing bag. It practically leaped on, and I did it easily 3-4 times and thought I was the shizzit, like I was actually getting a feel for it. Well, the TriX 320 had a totally different feel in my hands. It felt thinner, and kept wanting to bend, and as careful as I was with it, it continued to slip. There were a few times I felt like I got it started but it refused to advance, and when I tried to adjust it slipped off again. I was being as patient and careful as possible, but after about an hour, there was nothing else I could try, plus my hands were getting sweaty in that bag, making handling even more difficult. I gave up. :x
It was awful and now I'm intimidated by 120, which I really hate to have happen because I'm intimidated enough by all of it. :? Can films vary so widely in thickness that it affects handling like this?