I am using a combination of itti bitti smalls and tuttos (the tutto's I like in particular), issy bears OSFM (which I also love) and BBH bamboo fitted (not so keen). I've used them since he was 2 weeks old (he's 5 weeks now) and thus far the only time I've had a poo leak was when I didn't do one of the itti's up properly when I first started and didn't follow the instructions. The lack of leaks is despite him having large BF poos that come out with lots of pressure behind them (it doesn't help that mum likes her cabbage and cauliflower either) - I've actually had him leak in expensive Huggies at least 3 times already. However, my bub was a big boy (4.2kgs born and only lost 60g in the first week) and has short chunky thighs. When he was a week old I placed him next to a friends baby who was a average 3 month old and they were the same size, so I don't know if my experience is anything to go by.