Soul Sparkle is currently known to be Dominant to at least Tap Allure.
If you breed a cat with Soul Sparkle eye showing to a cat with a more recessive eye (from further down the Dominance charts), you should have at least a 50% chance of getting Soul Sparkle back as a shown eye on the kitten. There is always a 50% chance the Soul Sparkle-eyed cat will pass their hidden eye color instead... and in many cases that hidden will be something other than Soul Sparkle.
*Was typing at the same time as Ivy, smiles. She's given you the links to the various charts for keeping track of traits and relative Dominance.
