1
Right now, he uses (I believe) a 34-inch, 34-ounce bat. He's a big strong man so he doesn't need excessive bat speed to generate hard contact. So give him a 32-inch, 36-ounce bat and have him choke up two or three fingers above the knob and tell him to try to use a pepper swing unless he gets exactly the pitch he wants.
It doesn't have to turn him into a .250/30/80 hitter...I'd settle for .210 20 50