In case anyone is still following Spot's feeding "saga" I wanted to update I'm relieved that he finally ate today! I was thinking maybe the baby rats were just way too small and they were confusing him. As I said, he came with those when I got him, and I was trying to use them up.
So this morning I covered his cage, made the room dark, and gave him a bigger rat. He grabbed it by the front arm for the strangulation and I was thinking it's not off to a great start. But I just left him alone and gave him 30 minutes. When I peeked in again he was just swallowing the tail. :-)
I do wonder still how they make it in the wild if they are this finicky and kinda not-very-smart with feeding.