Yes, you can adjust it. Bitzenburgers come with either a left wing, right wing or straight clamp. Loosen the set screws on the two knobs and turn them with the clamp on the jig and an arrow in the jig to position the clamp so it touches the arrow along the clamp's entire length. You can do a little offset with the straight clamp, and a lot of helical with either of the left or right helical clamps.
Should you have more? That's up to you. Even a straight fletch will spin because of the natural curvature of the feather. If you shoot with a lot of weight forward, not as much fletching or helical is needed to guide the arrow.