J.P.
I have some cotton strips that I use when I need to use diapercream. I actually put it on everynight to prevent diaper rash, and it works great. You can just cut up an old t shirt, or use flannel wipes.
What kind of diapers are you using. It is hard to give suggestions without knowing that. I have heard that hemp inserts hold more. My son is a VERY heavy wetter and we use BumGenius. At night we use two normal and one infant insert. By largest possible size, are the diapers sized or one size that adjusts? That could be part of the problem with the leaking, in that the diaper is too big. If it isn't tight around her legs and waist, it can leak, or wick out.
I use the Costco dye free, scent free detergent.