You are only allowed to drill holes a maximum of 4.5" deep, so that somewhat limits the maximum amount of weight that can be removed (depending, of course, on how many gripping holes you drill in the ball with the maximum now being 5 holes.)
I would think the weight coming out would also vary depending on whether the ball is a 2-piece ball like a Hy-road or a 3-piece ball.
Generally maybe 1oz per finger hole...possibly 1.5oz for a bigger thumb hole?
It is surprising one of the YouTubers hasn't done a before and after video for something like this. Would be more fun than your average reaction/review video for sure.
