The American and Italian leatherbacks are basically a visual het for scaleless. You get the same ratios as you would breeding 2 het trans(or two het hypos) together.

Het trans x het trans = 25% trans, 50% hets(normal), 25% non het(normal)

Het trans x trans = 50% trans, 50% hets(normal)

trans x trans = 100% trans

leather x leather = 25% silk, 50% leather, 25% normal scaled

leather x silk = 50% leathers, 50% silk

silk x silk = 100% silk

Josh