It depends on the current layout, your intended new layout, and your axis coordinates. Unless its a rare ball, perhaps you should locate one that already has the layout you are looking for. Then plugging and redrilling the ball to fit you will have minimal effect on the dynamics, and you won't have to worry about rolling over a plug.

everyone has their own opinions, and this is mine.. I will buy a lefty drilled ball to redrill righty(have done many times to sample a ball)as long as it "DOES NOT" have a weight hole.. yes, once in awhile you can get away with having a plugged weight hole.. my rule of thumb is don't take the chance that some plug(from any of the holes) will be in your track area.. better safe then sorry, once plugged no matter how good the person plugging it is, the ball is never truely round again.. remember this is just my opinion..

I've had two left balls redrilled for me, but the previous layout had the pin above the lefty's middle finger, mb stacked below, and no weight hole on either. All I had to do was plug the holes and drill back into the lefty's middle finger and thumb and create a new hole for my middle finger. This only left a plug to the right of my ring finger so its not on the track and the mb the strong position (thumb quadrant). I only buy used if the ball is exactly how I want it drilled so I don't lose much of the core and in this case only a bit with the one small finger plug.