The Gaussian strength is equivalent to knit balls of this size. The advantage of these are the stark
shade of white and the silence esp when using a leather chop cup, e.g.,
http://www.penguinmagic.com/p/S17665 (no longer available). There are complaints (see the smaller
set's comments) that the drop/hold is unpredictable. Well, kids, the balls are white and leatherish.
Use a pencil or similar and mark/scrape the location. You're suppose to cheat.