We started out with 1 tablespoon of cereal and 3 days later we were up to the full serving of 1/4 cup. I put 1/3 of a pack of fruit in with about 3oz of formula and it seems to be the perfect concoction. Not too runny to blow out of the mouth, but runny enough for him to swallow.
We are also giving him 4oz of juice a day right now. I'm not thrilled about it. I'd rather wait until 6mo. for that, so I think I might drop it after we get off the rice cereal and onto the oatmeal which will hopefully not cause so many constipation issues.
It seems that Ethan is completely ready to make the transition to real people food. He grabs stuff off our plates and opens his mouth like a little bird every time we take a bite. He reaches for our cups and we even let him take a sip once although most of it ended up on his shirt he keeps wanting more.