For the trough we can use a deep gouge, finishing the bottom as we merge into the sides of the bines. Again, it's all about feeling the form - the run of the barley twist - as you cut with the tool.
Ends: Make sure you run the line of bine and trough completely off the end of the barley twist, as if they were infinitely long. Thus the ends of the bine and trough will be sharp. Never round them over.