I don't even know if Claus still follows this forum, but I guess there's no harm. I tried the Necchi Supernova bobbin case in the Anker RZ, as both the cases and the bobbins look the same. Sewed the basic stitches, straight, ZZ, you know...I couldn't detect any difference in stitching at all, they seem completely interchangeable.
There may not be an abundance of vintage Necchis around, but they are easier to find than the Ankers. For all I know they still use the same case.
Stein