I feel the same.
Wouldn’t spider HAVE to be a co-dominant trait? Since it was proven allelic to blackhead? Would that be possible if the spider gene is dominant?
edit: the jaguar gene in carpet pythons is considered to be analogous to the spider gene in ball pythons, if I’m not mistaken, with the super being a leucistic all white snake. Very similar to the supposed stillborn super spiders. This is also a lethal gene combo in carpets.