I used a teaspoon every two ounces to start out. Just to help my little one keep formula down. He couldn't get full so would drink until he made himself sick. I think it is 100% okay to give your baby formula in a bottle. I started my baby at 2 months and he did great
None. If a baby needs it, it's meant to be fed with a spoon. Otherwise your just going to tear your childs stomach up. If your having issues with reflux, there are formulas with the proper amount of thickening agent in it.