My DD was feeding 3hrly till she was about 4-5 months old - I just went with it and she was usually polishing off 240 mls to 260 mls in a sitting. When she was 6 months she stared to go 4 hrly as she was having some solids as well. She used to sleep 6.30 till 6.30 over night after 3 months so it was only day feeds as well. My MCHN told me to always make the bigger amount on the tin so then if she wasnted more it was there and if she didnt no biggie.

HTH