Punch and hammer
I cut some angled wood supports close to the hub, and that part took the most time. 3/8 punch, 5 lb hammer, not a lot of swing, and < 2 minutes later the spinner backplate was free of the prop and extension. Working evenly is the trick. Reassembling was the same. I seem to remember either the saber or Sensenich instructions noting a whompum stick was required for assembly. If you use oil, make sure you get it all clean before assembling to the hub. You don’t want oil between the hub and the extension or extension and the prop, and oil on the bolts will give bad torque readings.