I renovated the bathroom recently, and along with that comes replacing the
shower head arm (old one is the wrong color now)

The new one is about 9" long and has a slight bend in it, intended to aim
down. HOwever, when the thing is tightened in place, it's aiming down and to
the left. I need it to aim straight down. How do I get it to do that -and-
have it tight?