I bought 2 of the 60ml bottles to allow my baby learn to hold it. It seems easier for him to hold the smaller one at the start and he was alr able to hold it himself at 3+ months. But I also alternate with the bigger bottles so you may want to mix
i would get the second smallest so can last longer, the teat is the more important factor. I would suggest 6 bottles so you don’t have to wash too frequently, and there’s enough for ppl to take over feeding if you need to rest/fall sick.
I’m also a FTM, personally I think 6 bottles are just nice. Enough time to wash and sterilise. I’m using the 120ml size
120ml. I bought 3 and baby outgrow them around 3mths. Baby will most likely outgrow 60ml in the 1st mth~