This page is all about getting the spinner well aligned. Take out the plugs so you can rotate the engine, tape up the prop blades to prevent scratches and clamp the spinner to the back plate. Then turn the prop and verify that the pitot tube doesn’t wobble (thus indicating that the spinner is well positioned. The Book recommends taping a ruler to a chair to position it right in front of the pitot tube so you have a good visual reference. I couldn’t get the ruler taped juuuust right, so I used my micrometer so I could adjust the tip.
For the photo, I put a light source on the (clear) pitot tubing behind the gearbox and it very nicely illuminates the inside of the metal pitot tube. Nice!