I believe that if you drill the weight hole with a big radius and not that deep the reaction will be smooth, and if you drill the weight hole with a small radius but deep, the ball will have a more snappy break to it, i'm not sure, but i think that's how it works.
--------------------
The self proclaimed "confined mind"
"I've got to stop Babara Striesand from taking over the world" - Robert Smith
Snowboarders kick @$$!