First, if your rifle is new, it will require at least 500 shots before it gets to point when it will begin to shoot in a "groove." Some rifles take 1000 shots. Good groups will come in time as the gun works in and you learn to shoot a springer.
Nevertheless, I would begin to try different brands, beginning with one you might prefer to shoot and come back to as a base measure, say, Crosman Copper Heads. As the shape and weight of the pellet changes, the impact point will vary accordingly, as with any projectile.
Incidentally, be sure not to leave the spring cocked for any length of time, as it will gradually diminish in strength.
You can then try the heavier Beemans and whatever, keeping general records of how they shoot.
Each rifle varies, so you will have to experiment.