Guys run it both ways with spawn sacks here. Some will create a staggered shot pattern (large ones on top, descending in size to within about 10 inches of the hook) with a very small split shot ticking bottom. The trick is to load the float so that it becomes unstable, and dives when the fish takes the eggs. The purpose of this set up is to run the line in a straightline all the way to the bottom shot, which allows the lighter spawn sac to be in the fishes face before the sinkers get there. You don't have to tilt the float stem up river to pull this off. This is used mostly in what we call "frog water".

The other method would be to put a couple of heavier shot close to the float, and then a couple medium sized shot about a foot above the eggs. This rig is run about 6 inches off the bottom, and is used when you are putting just enough pressure on the float to lean the stem upstream. This also puts the eggs in the fishes face first, and works good in a little heavier current.