best advice I can give would be to research the differences between dominant, co-dominant, and recessive. dominant genes (alelles) will look the same whether an animal is homozygous or heterozygous, and there is no super form, e.g. spiders. co-dom traits like pastel, lesser, mojo, etc. will look different from the wild type and different from the super form. that's why it's not technically inaccurate to refer to a lesser as a 'het' because it is heterozygous, with the lesser mutated allele paired with a normal. however, it's more confusing to use the term hets with co-dominant mutations because, as Judy mentioned, there are several mutations that yield a leucistic in the super form, e.g. yellowbellies, russo, fire, lesser, mojo, etc.

having said that, it is helpful to think of co-dom snakes as 'heterozygous' for _____ because there is a difference between the heterozygous and homozygous forms. it will help you understand the differences between a pastel and super pastel, a lesser and a lucy, etc. because the super form is the result of a homozygous mutation on each allele.

my apologies if I've only further muddled things, but hope that helped a little. as mentioned previously, for your own purposes, if you pair a lesser with a normal, each egg has a 50/50 chance of being a lesser.