I top up at every feed and have done for 5 months (long boring sob story) anyway should I buy the faster flow teets for 6month+ or can I do a DIY job and add some holes or should I just stick with what I have - she doesn't seem too bothered but first baby and so I don't know if its a good idea to move to the faster flow ones...sometimes she is falling asleep on her last bottle of the night and I wish she could down it faster as I prefer to put her down to bed still awake.