I know the head wobble is common in the Spider and Champagne morphs but I'm not sure its limited to just those two genes. I've never heard of it in a super pastel, although I would be interested to see if either of the parents had Champagne or Spider in them, perhaps somehow it crossed over to their offspring and is maybe not 100% connected to those genes. I'm also wondering if it could be heterozygous for a recessive trait that could be the culprit. I saw a Champagne baby in the pet store and it was so wobbly it was upside down just trying to crawl around.