My split rock has 4 leaves, should the outer leaves be removed at some point to prevent stacking in order to prevent death of plant, and if so how do I do it?
The best way to prevent multiple leaf pairs is to stop watering when they are growing the new set. These kinds of succulents take the water and nutrients from the older leaves to grow the new ones. As for your current situation, I fear removing the older pair would do more harm than good. You may try not watering it for a while so it'll use up the water from the older leaves, but having just two leaf pairs shouldn't put much stress on the plant.
Well a photo might be helpful, but split rock plant (assuming you mean Pleiospilos nelii, image here http://www.ctsairplants.com/Split_Rock_Succulent_Pleiospilos_Nelii_p/pleiospiosnelii.htm) has either 2 or 4 opposite leaves. Unless yours is growing in a peculiar fashion (and without a photo, impossible to know) there should be no need to remove any leaves.