Redrilling the ball will not harm the ball as long as it's done properly. I have been thinking of doing mine soon to get the span changed. As far as the weight goes, they wouldnt have any weights added that weren't in the ball from factory, as it would be against the rules and impossible to do. Most balls have a certain shaped core that react different ways. The combo between core, coverstock and drilling is what gives you the amount and type of hook...aswell as overall skill of course.
But about the wet lanes shot, try keeping the way you throw as is, but move further right and aim for the same spot. Should work out with a little tweaking. Depending on the lane condition, you have to adjust accordingly.