I haven't read every post so don't know if someone mentioned this tip earlier.
I got a Sidewinder for Christmas but I have a Viking Sapphire 830. It didn't work on my bobbins, but that's because the thread unwinds the wrong way after being filled. I found if I put the bobbin in upside down, it winds the bobbin correctly and I can use the Sidewinder if I want to for my Viking.