Finally I have finished this project. I did it very simply this time, as it is just meant to be a temporary haft so I didn't even use the holes. I simply cut down a piece of willow with my antler axe and split it with my antler wedge.
The head is inserted into the crack and the sinew rope is wound around it. To keep it from wobbeling in the crack, wind around the head as shown in this rather poor drawing.
The pick in use.