No, if the overflow is 800 gallons, then the return pump must be able to match that output, taking into consideration and head pressure and right angles etc. in the plumbing.
The pump on the skimmer shouldn't really make a difference because all it is doing is circulating water that is in the sump. It is not putting more water in, and it is not taking any water out. Putting the skimmer into the sump is a lot like simply dropping a power head in the sump. It is just moving water. Whether it moves is quickly or slowly, it is still not adding any water to the sump, or removing it.
Imagine if you had a refugium operating and had a power head in your main tank. No matter how powerful that power head is moving water in your main tank (unless of course it is so powerful it is actually pushing water over the side of the tank), the water is still going to rise in the tank as the refugium pump pushes water into the tank. When it goes over the overflow drain, it will go down into the sump.