The original on IAP is here:
Imported Photo from leehljp. Please edit title and description.
www.penturners.org
IF you are using standard bushings, most ANY angle works fine. If you have custom bushings for 60° centers, then of course 60° centers are required. The reason for the long nose on the photo above is that I had nothing to go on and I was living overseas. I did not have a dead center and didn't want to wait for one to arrive from the USA, so I made the first thing that came to mind - out of aluminum stock. At that time, there were NO 60° bushings for live and dead drive centers. So most any angle was acceptable for standard bushings. That was back in 2007 or 2008.
Shortly after that photo was presented on IAP, several IAP members here (USA) started using 60° live centers and drive centers, then John Goodin began making 60° bushings, the first person that I know to do so.