Thanks for the follow up. The red and black rings are common o-rings purchased from
http://www.allorings.com/. The black one's are "Buna-N" and the red one's are "Silicone". They have dozens of different sizes...my pens are pretty thick (large), so I'm using a "-007" that measures 5/32" ID, 9/32" OD and 1/16" wide. The 1/16†ring width is the smallest they make, and its still pretty wide. So, I always use a smaller ID o-ring, relative to the OD of the pen, that has to be stretched tightly around the piece, thus making the ring thinner, and I think…more attractive.
On the bowling ball finish, I've found that some colors (red, blue, purple and green) polish up better that others...its harder to get the white and yellow to shine. The finishing process I've centered in on is: sand from about 120 to 600 grit in progressive 80-100 grit increments, then put one or two coats of sanding sealer on the piece, wiping off the excess quickly (before it dries) with a paper towel. Then I use the three-step Beall buffing system to remove fine scratches and polish the piece. The sealer is applied to fill any of the little pits (pinhole air pockets) that sometimes show up, before buffing, to keep the Beall tripoli and white diamond out…the tripoli is brown, and looks bad if it gets into any tiny pits in the light colored blanks. Likewise, the diamond material is white and may leave some freckles in a dark colored piece…so use the sealer before buffing.