I used to do it all the time, as that was very important to me then, and I did it this one time on this “early” Rose cake. Since then, though, I don’t really change the sweetness of her cakes, because they’re not as sweet as other recipes. The cake is a tad denser, but still very moist and very, very soft and delicious. Truthfully, I don’t think you’d even know it was modified unless you were doing a side-by-side or really “knew” a particular cake. The milk worked great—I used it because it was the cake’s “liquid,” but my comment about using water was motivated by thinking that the liquid in sugar is water, not milk. But there was no ill effect using milk.