All the shot under the float except perhaps for a small dropper about 6 inches from the hook.
A good float to try in these circumstances would be a loaded drennan puddle chucker shotted in the same fashion.Less splash when you strike given it is a bottom end only float.
Mark describes in pictures the Trent Trotter with a couple of shotting variations.
If you cannot get a Trent Trotter then you can easily make one by cutting off the stem of a decent Avon float and whipping an eye on the stub. Alternatively use a waggler silicon adapter as this will also reduce the 'splash' on the strike.