Some words about hedcut technique.
This is one of my recently done hedcut for one web project. The number of stipple portraits drawn for this client is already over than 30 and I was very happy to work with them.
When you draw for the same client for years the most difficult thing is to keep the style which you have been using all that time for his portraits. Dot size and detailization level should still be almost the same. You draw portraits for another client with differents requirements and it may cause the changes in draw technique. What you have to do here is to keep an eye on previous hedcuts from this series while drawing the next one.
Finally you learn to switch easily but this is the dead end track. What you really need
is to find your own comfortable technique and fill your portfolio with artworks that don't change too much from each other in this sense.
As for hedcut drawing it means to find optimal combination of dot size, contrast level, hatch or crosshatch. You need to decide for how much you allow yourself line using and a lot of small defferent things which make your stipple portraits recognizable. For example when I see hedcut artwork online I definately can say is it Kevin Sprouls or Noli Novak, or Randy Glass's hand. One day I will write short review about their technique differences.