I've made this soup twice, second time I used more potato and it didn't seem as flavorful, not a lot of leek taste, which is understandable. Is there a proportion of leek vs. potato to follow for best results? A recipe in Bernard Clayton's soup cookbook says that french peasant households use equal parts, and water. Question: is chicken stock necessary? Also, I sauteed the leeks in butter first. Clayton's recipe just throws everything into one pot and adds butter to individual servings. Any ideas?