Waterproof pants work with a cloth diaper by providing a barrier until the cloth diaper can catch up to the flow by wicking the wetness to a dry section of the diaper. Once a cloth diaper reaches maximum capacity, the pee will pool against the waterproof pant and leak - by wicking through the fabric covered elastics.
With a waterproof pant over a disposable however, there will be no pee between the disposable and pant until the disposable diaper has reached capacity. Once that happens, you will have leaks. A plastic pant over a disposable is only going to buy you a little extra time to change.:sweatdrop: This is not a workable solution for night time diapering
So what you need for overnight is more absorbency. You can get this by adding boosters to your diaper or wearing lined plastic pants over your disposable. These pants have a lining of terry or flannel and are called "trainers" or "All-in-ones" in addition to "lined" pants.
Edley Lang makes a great lined plastic pant that have 2 layers of very cute patterned flannel. The flannel lining has elastic leg gathers separate from the plastic pant. The plastic and flannel are joined only at the waist and the waist band is completely encased with the vinyl to reduce wicking at the waist band. This design has 2 advantages. It greatly facilitates washing and drying since the flannel and plastic separate when you turn the garment inside out. And secondly, separate leg gathers reduce wicking through the fabric covered elastics. This pant is available from Life Style Emporium
www.lifestylesemporium.com and for a little while longer from Changing Times Diaper Company
www.changingtimesdiaperco.com/