Just Reverse Head and Tail

[numbskull]

As you have noted, both pencils (when worked slow) and spooks/howdies will veer. The shape is not the determining factor. What makes a plug veer is the tail weight pushing against a buoyant nose. The momentum of the weighted tail of the plug, when twitched, pushes the light nose out of the way and off to one side which makes the plug veer. This is why pencils and spooks don't work as well with bucktails. Unless the dressing is very sparse, the drag kills the momentum and deadens the action.