How do you keep a prop centered on the prop saver if the prop saver is too small for the hole in the prop and it tends to wobble?

Does the prop saver have a wider hub on the back side?

Besides that, if your prop didn't come with bushings (like APC electric props do) the only other option is a different prop or a different prop saver.

The other side of the prop saver has a v shaped hub but the prop could tilt on it. Ron

My prop savers are a little small for the GWS props I am using. I use the deep "V" side and find that the prop self-centers with no vibration if the O-rings used to secure the prop are not too tight. I loosen up stiff O-rings by flexing with some needle-nose pliers. I have found the prop savers to be very effective.

I use the cone-shaped side of my prop saver with my GWS props, the ones with the nut cutout on each side of the hub. They fit and center just fine.