Gramps,
For foam incorporated into cork grips, sandpaper on a block of wood has always worked, so when the grandkids needed spinning rods, I used dry wall sheets and sandpaper on 2-5" sections of EVA to customize the shape. It worked fine. I found I could cut off a short section, like for a 1/2" winding check, or part off a 2" piece from a 10" starting piece, with a sharp skew point. It's been a while, but I think I tried other turning tools to shape, and stuck with the easy and tested 120 grit tool. In the cobwebs is the thought that maybe plain sandpaper worked better than the screen abrasive, but no reason not to give them both a try. I did find out there is a difference between EVA and Hypalon. The Hypalon is harder/denser than real EVA and doesn't shape as easily, even though they look the same.
Dean