Hmmm... we didn't get on at all well wit the Bamboo Baby Behinds when Erin was much smaller (we started trying out different types/makes of nappies from ~3 months). They didn't fit quite right, especially round the leg, and the poo tended to squirt out the sides

They do fit her ok now though! I randomly decided to try it again just this week, with much better results
By far & away the best all round fit and the ones she seems most comfortable in are the Little Comfort Bamboos.
Not sure how well they'd fit from teeny-tiny as we didn't use cloth nappies from the outset, but at 3 months, Erin wasn't particularly big and they've fitted well since then
Dooby x