Well, i used a mixture of fitteds and AIOs. THe AIOs i had were small ittis and NB babybee hinds. THe bbh were awesome but yes, the ittis leaked sometimes cause if the leg gape. Didnt bother me though cause they always leaked on dh and never on me
The fitteds i used were buzy bee. I plan to throw in some prefolds for this one also.
Btw, i had a skinny bubba 3kg's so i would think you would have to fit in the chunkyness factor too. Also fwiw, i bought the newborn sized bbh on special for a really good price other wise i wouldnt have bothered as they arent in that tiny size for that long - which is why prefolds are great as you can use them for stuffing or boosting later.