I normally use the "Pincer" type shown above, plus a nail file.
On 9 fingers, the issue is to keep the nail short enough.
On one finger, the issue is to stop the nail wearing away - it gets worn by down-strums on acoustic guitar or 'clawhammer' strokes on the banjo.
Recently I've taken to having an acrylic nail on that finger (local nail bar)... helping so far, but is even really hard to cut when it starts to grow out.