Hi My girl is coming to 6mths n i have inteoduced her NUK bottle sippy bottle teats look alike sippy cup.the bottle can drink up to 150ml n now her appetite gerting bigger she drink 240ml so i get e bigger one 12-18mth cause can drink up to 300ml. However, she tried this new bottle milk flow from e side n i feel too fast. Do they sell the sippy teats?