Hi, new guy here. My father in law just got out of the hospital and asked if I would install a couple of grab rails in the shower. It's tiled and I was going to put in two stainless grab rails, the rail I was looking at had three screw holes in a triangle pattern on a circular plate to hold them on and come in different sizes, should they be in increments of 16" to hit a stud? He wants them mounted horizontally. Question: The screw pattern is wider than the studs in the wall, how do I do this and still have it mounted solidly? How do you find a stud behind tile and how do I avoid hitting a water line? Thanks!