Would going from 3k to 4k help tone down the ball reaction some? Or would just polishing do the job? Or would I need to do both? Ball is picking up too soon, and jumps at the pin deck more than I want it too.
Since that is such a slight adjustment, its effectiveness depends on how speed dominant or rev dominant you are. If you're closer to being rev dominant, it should help a little - so it also depends on how much later you need it to react.
If you're rev dominant, try to make that adjustment with a wet new pad by hand, not on a spinner. If you're speed dominant, sand it to 1000/1500 grit and put a medium polish on it so that you can still see the sanding lines underneath the polish and you have some degree of shine to the surface.