In my mind's eye Rudi Skadi has always been a bit of a '16 valver' as they say.
I never really considered Ruta Skadi all that attractive. As Owatts said, she was described as beautiful but with little character. I need to get reasonably attached to a character to really consider the details of how they look, and I never really got attached to her. Something in her personality seemed lacking and I didn't give her much thought, at least not the first time around. I'm rereading them at present, though, so maybe that'll change.
Of the witches I always imagined Serafina the most attractive. She has that sweet, motherly side, but also some sort of implacable quality; I don't know, just being a witch and a clan-queen shaped half the image in my mind and her personality did the rest, so I see her as classically pretty but... Gah, I can't quite describe the physical quality. *sigh*