There is no need to let it wait and soak for 10 minutes and then drain slowly. All you need to do is add all of your sparge water, stir, open up the valve, vorlauf, and let it flow as fast as you can. The idea of batch sparging is to simply get all of the sugars in suspension and drain them out quickly. Fly sparging is slowly rinsing the grains. You can definitely cut some time off your brew day. Also, why are you doing three runnings?