Hi Kent, 

I do like the Dremel idea; it will allow you to section the WOB and remove it like a dentist removes a wisdom tooth. 

I wanted to let you know that every time I have ordered prop shaft zincs they have come with the plastic screws.  The zinc has exhibited “normal” wear but has never fallen off.  The Autoprop website has a video showing the rebuild of an H5 and references removing the plastic screws when disassembling the prop.  I believe metal screws provide a preferential contact area on the mounting tabs enhancing the destruction of the tabs whereas the plastic screws spread out the contact area to the body of the zinc – just a SWAG.

Good luck with your project.