@glennf, that cut has no hair details at all and has too much space beneath the chin, 2-3 pixels should be enough. At the same time, we also expect each cut to have a little bit of collar. Since in some sources, like this one, the person in the image may have a longer neck than usual or the collar is lower down, this would be quite difficult to achieve naturally. Here's a technique of how this can be accomplished quite easily:

The pending source should provide a good cut anyway, so give that one a go instead, using the above technique 👍