|Too light weight, they easily topple over.|
I shouldn't be so hard on myself. Years ago (and still in storage out of state) I had several cone holders, similar to this one.
And yes, they are nice, especially when the little cones get empty. But you know what works, and is readily available in the work areas of most machine knitters?
A small weight from a Japanese machine works wonders to keep a lightweight cone in place as the yarn is pulled through the machine. And it fits perfectly!