Well from what I've seen, there are ways to tell the difference. Correct me if I’m wrong.
Super Lessers or Super Butters produce white BELs (sometimes with bug eyes)
Super Mojave have the dirty greyish head
Super Russos have a faint white line along the spine
Lesser/Mojave BELs Pure white, with a faint yellowish line along the spine as they age.
Lesser Pied produce the whitest BEL, with small black eyes
Super Fire (Black Eye Lucy) Can produce all white snakes with black eyes, sometimes with orange/yellowish patches
There are other ways to produce BELs....But I'm not familiar with it. Good luck!!