I am looking for a walker for my son. He's almost 15 mo. and a little behind on his gross motor skills. He's just starting to show interest in walking now. I'm trying to find a good quality push and walk behind type of walker. At the moment he's trying to use his activity table for this purpose Does anyone have any experience with these?? I need something that will not tip easily, will not go too fast on hard floors, and is not too short, he's a very tall boy at almost 3 ft. Any advice will be appreciated