Here we go, a baby feeding guide. Don't know why I couldn't find this this weekend when I looked, but here it is. We've already started with thicker rice cereal than that, and Cale likes it. He acts like he would happily take more breast milk if I could make more. He's right on target gaining weight (shucks, 80th percentile; I'd be worried if he weren't breastfed), but he's also the weight Karston was when he was 9 months old. Karston had other calorie sources then! Certainly Cale seems to appreciate more calories. He's fascinated when we eat, and he really goes after the spoon.
On the other hand, he has only pooped once since we started rice cereal this weekend, so maybe that's why you're supposed to mix it thinner than we've done so far. Let his digestive tract adjust?