WHO havent changed reccomendations and still states no solids before 6 months. 4 months is way too you IMO. I too have had refluxy babies. Solids didnt make an ounce of difference (only time did... you cant force their bellies to mature) in the vommiting. Sorry to be blunt, but if bub is still bringing up formula when its thickened (its just thicker now yeah?).. solids wont make an ounce of difference.