I love CDing!
I bought some Bambino Mio wraps from a co-worker that are great for under clothes because they are more contoured, but they leak, and so do most of the other wraps and the pocket diapers I was given, but my Mom got me a stack of dri-line snap to fit wraps that never leak as long as I don't have any of the pre-fold poking out by accident. The very edges, the binding around the sides sometimes wicks a little, but only after she has been wearing them for over five hours (at night).
I think the best absorbency comes from the cotton Bambino Mio prefolds. They also seem to wick the moisture away from her skin better than the waffle weave ones my mom brought down.
I also have experimented with putting a fleece liner (just cut a bunch of rectanlges out of a fleece receiving blanket) above the prefold so that the moisture come away from her skin at night, which helps.
site also has quilted baby pads that would be great under layer to protect the baby from any possible leaks.
I am excited about trying to make a few AIOs for travelling purposes.
ETA: we do EC by day as much as we can, but through naps and at night I use the cloth diapers...sometimes she just lays out on a few prefolds with a square of shower curtain laid beneath her.