Cloth inserts with disposable?

We use the up & up disposable diapers, and most of the time they are great. They only problem is that he leaks through overnight, so I was wondering if anyone has used cloth diaper inserts inside a disposable. I know it sounds kind of strange, but we are trying to do something more economical than buying a more expensive diaper. I was also wondering what kind is the best, and if anyone has used the Gerber birdseye cloth diapers. Remember, we are just looking for some extra absorbency overnight.