Baby "S" is an extremely heavy wetter. I have tried double stuffing numerous brands of pocket diapers and she still manages to wet through them at least twice each night. So I tried a fitted with a cover and it worked pretty well but Daddy "S" and I didn't like how wet she was in the morning. Finally, I settled on an option that seems to work very well for us and finally we're very happy with our night-time situation. Here it is:
First, we put a Bummis Fleece Liner inside the diaper. The diaper is a fitted diaper that has cotton on the inside touching baby, zorb layered in the middle, and cotton print on the outside. The diaper is $8 for a large (gasp!), high quality, and made by handsewnbyme. We put either a Zookies (review coming) or Bummis cover on the outside.
This system is amazing! It keeps all the wetness from leaking through because the entire diaper is absorbent. Not to mention how absorbent zorb is! The liner looks so incredibly thin I didn't think it would do anything, but it seems to wick the moisture away from Baby "S" so when she gets up in the morning she doesn't feel very damp at all. I'm not sure that it really adds much absorbency but they are so thin you could layer multiple liners in the diaper to truly add more.