He might not eat all of that from a spoon. I would start with 2 tablespoons of cereal and add liquid until it's a good constancy. Not to thick but still solid enough to stay on a spoon. Then you can make it thicker or thinner when you find his preference

Yeah that's what I did

@abeals04, my son eats 6oz too, so 6oz of milk and then add cereal til i feel like its good?

I do it by sight just do its so it's still a little liquidity and then as you go on you just add more it all depends what you're child eats my son will eat six oz of formula on to of the six oz of formula I mixed into his oatmeal