Thanks for the additional pics!
That’s better care advice than many places give people still today. It’s really quite appalling how little so many who sell them know.I had one for a couple of months back in the 70s when I was a kid then it died. I didn't really know much about them other than what the salesman told me which was to feed and water them and to give them different sized shells to try out and see which fit it better. It was interesting to watch them switch around checking them. He wound up going back to the one he started in.
It makes perfect sense. If you watch the birds they do something very similar.So far, no! I have thought they might be hung up a couple times and have considered removing it but the littles especially seem to enjoy messing with it. that is more ‘their’ end of the tank anyway, and the jumbos like the end with the big wheel better, although they can all go most anywhere in the tank- if that makes any sense! They all fit in most all spaces but one end has more tight corners and the strings etc to contend with.