In 1960 or so, got my hands on a drill press and table.   Did not have a dodo scale but knew what weights I had.  I put a 3oz weight in every position you can dream of in a 15# Black Udot.  It originally had 3oz TW.   Some positions made the ball unusable.  Just a crazy hop wobble type thing.  That ball got mean with 3oz on Positive axis point.  It got even better with 3oz on Both axis points.  Buried 6oz deep into the ball, as close to center as I could.  You could see the roll  emphasis change.   Now, all these effects are legal. 

  In 1960 or so, got my hands on a drill press and table.   Did not have a dodo scale but knew what weights I had.  I put a 3oz weight in every position you can dream of in a 15# Black Udot.  It originally had 3oz TW.   Some positions made the ball unusable.  Just a crazy hop wobble type thing.  That ball got mean with 3oz on Positive axis point.  It got even better with 3oz on Both axis points.  Buried 6oz deep into the ball, as close to center as I could.  You could see the roll  emphasis change.   Now, all these effects are legal.

Legal for everyone equally.  People have been calling for static weight changes for a long time.  Of course they only fix it once I have a half dozen balls drilled with a balance hole but hey better late than never right?

Columbia U-Dot wasn't made in the 60's! It was a urethane ball and all they had then was polyester/plastic. Just my $.02!

I don't drill balls, but how do you get 3 ounces of positive on both axes? 

 Flip the label over on one axis, then drill a large hole on the other axis. In the hole, you fill it with something significantly heavier than the balls material, and plug it back up.

 The label puts three ounces on one axis, and the illegal plugging puts three ounces on the other. Yes, it is illegal, but people used to experiment with stuff like that all the time.

 You would be amazed what I’ve found when redrilling some older balls back in the day.

If a ball has +3 oz side weight, then in theory wouldn't the other side of the ball have -3 oz?  If I drill a hole on the negative side and add weight to achieve +3 oz side weight on that side then the previously positive side is now negative?

Isn't the whole idea of statics based on the difference of the two sides (side to side, top to bottom, finger to thumb)?  To me, no two compared sides could be positive.

Yes if both sides had the same weight, there would be zero side weight.

So if there was +3 oz side weight and you add 3 oz to the other side, the side weight would become zero for both sides.