Help me with pickup screw adjustments

I am setting up my valentine guitar. I have a newbie question. My valentine humbucker has 2 screws on the bass side and one on the treble. Are they all adjustment screws or are some just for mounting the pickup? Also I was surprised that music man called for the neck pickup to be higher then the bridge. Thanks in advanced and feel free to add any other set up tips. My neck is pretty dark with the tone all the way up. Curious if adjustment could slightly brighten it.