Depends for sure on the paint but its either the Blue, the Super soft (white or red) depending on size.. OR the Hydrotech Crimson which I LOVE for reflect on harder paints. The best I have used and my new favorite for finishing is the Scholl Concepts Neo Honey Gold but I know not many of you have that in your toolbox yet as an option. You should be able to get great results with one of the other 3 I mentioned. Basically either a very soft foam, the blue BS, or the HT crimson.
Of course if you were one stepping swirls then you would go with something like the orange -