DS is 4.5 month old. We are looking to buy a seat so we can feed him solid. He is holding his neck fine when we carry him. We tried the bumbo from a friend and his neck wobbles quite a bit. Also, he is very chubby and his legs are too fat to fit into the bumbo. We have to push them down in place. He looks so uncomfortable. Now, thinking snug and ingenuity. However, i can't find much info about these seats. Are they suitable for baby who is learning to sit?