you can of course adjust the entire pickup up or down and change the angle, bringing up the bass side a pinch.
in general you don't want that pickup too close to the strings, there's a lot of magnet pull. they should live well further away than fender pickups, for example.
dropping the pickup also decreases the differences in output between one string and the next (the whole magnetic inverse-square law and all that).
i don't think it's very safe to try and push the polepieces themselves around, you risk breaking a coil wire that way.