I’ll narrow this down to three body types of float to make things simple – pencil, slim and bodied. They all have a part to play, but there is one definite all-rounder there, and that’s the slim.
The size of the body governs how much resistance there is when moving the float or trying to hold against it.
A pencil float is so slim that there’s no resistance, so it’s no good for days when you’re nailing a bait to the bottom and waiting. Instead, I’d use it for speed fishing.
A bodied float is super-stable but there’s some compromise in terms of how well it will show tiny bites.
That’s why the slim float is king. Narrow floats like the F1 Slim or Chianti still have some body to them, which creates stability but not by sacrificing delicacy.
In sizes below 0.5g, there’s nothing to choose between a slim and a bodied float for presentation.