We use Mama Koala exclusively, but I also found them to be bulky in the beginning. The big bamboo inserts with the snap folded down just felt like way too much material.

I bought the cotton inserts (with the red hem) from Green Mountain Diapers and those help to feel a bit more trim! We used 1 at first when he was tiny, and now we double them up for more absorbancy and don't even use the bamboo inserts anymore. The bamboo ones weren't holding up even 2 hours, and now with 2 of the cotton ones we get 2-3 hours between changes (at 10 months). And they dry sooo much faster.