My son started eating 6 ounces at 4 months. Although hed sometimes eat 4 oz as well, mostly 6 though.
My son was ate 4-5oz until he was 6 months old. My daughter was eating 6oz at 1 month. Every baby is different but if she cries for more I would up it a half an ounce to an ounce.
I've been told not to give her rice cereal ever because it has no nutritional value. I'm going to up her feedings to 7 ounces and try to give her 5 bottles a day instead of 4 @lovelily