Mike,
There's a lot of different ways to rig presentations under a float. Some guys line the rig with shot starting big on top and scale down to the swivel and so on but for the water I fish I like to keep a stealthy presentation which uses very little split shot weight or none at all relying on the weight of the fly to take it to depth all pending on water conditions and if the fly has been tied with its own lead core or not.
Its all about water conditions,silty,deep and fast,deep dead drifts or very shallow.... Thats where your split shot or lack of it will make all the difference in the world.