There is no proof on spider x spider being lethal. It might be, it might not be. The argument for it possibly being lethal is the neurological issues in all spider ball pythons. Other morphs with neurological issues tend to be lethal in the super form, so many believe that spider x spider is lethal as well. You can go with the banana spider x lesser bee pairing, but there's not really much of a point. However, if you want to add something extra, you could try a lesser pastel or something like that. Albino x albino is not lethal. You would get all albinos from that pairing.
This site has information on the known defects linked to ball python morphs. Hope this helps!![]()
http://www.owalreptiles.com/issues.php