Step 3: Cutting out the parts
In order to get consistent circles and speed up the process I made a simple jig out of 1/2" mdf and a finishing nail. With the jig in place it was easy to set the distance from the blade and drop squares of EPS onto the nail and spin perfect circles. For the top and bottom caps I also ran the discs through again at a 45 degree to remove as much material before I had to start sanding. I'm sure you could also cut the circles using one of the many 'ibles on hotwires as well, but I had a bandsaw so that seemed easiest.
For the inside circles I used the extendible exacto knife (i'm sure there was a better way to do this, but the knife was pretty fast and the inside didin't have to be perfect.