Location: Yorkshire, UK but my heart lies in Scotland!
Posts: 28,196
Red yarn may be a little thin for a hanging tube as I would worry the hammy could get its leg caught and wound round yarn and hang itself. A long shot I know but feasable. I would say you would be better with plastic ties pulled quite tight so nothing could get jammed in there or maybe thick cotton rope. If you see it being chewed you would need to rethink this.
string is not a good idea to have in the cage seeing as the hamster could start chewing it also possibility of getting it caught around a leg or something...