I did the yarn thing a couple times with Kupo, when it looked like his ears were "sliding". I glued it between the ear tip and the hair. They were about an inch apart with the yarn on. I did it like that for a couple months. Now I don't feel like I need to use the yarn anymore. At rest, his ears are right on the corners of his head. When they are erect, they're now about an inch apart. So I feel like the yarn worked well.
I didn't get that from his breeder, just decided to do it on my own

So I'm glad it seemed to work out!