He was in this very bad habit of napping / snacking every 2 hours. 4 hours seems to be when he gets hungry I think I will stick with this.
Hun, you're his Mum and you know him best, but 2 hrly feeding is common for babies this young. Even on formula his tummy is still really small and he may be digesting his milk that quickly. 'Snacking' is not really likely when he's so small.

Maybe try shortening the time between his feeds during the day and see if this makes a difference for him?