It depends. The "rules" ie above post do not work if those using it are not 'average' height. If the person who really needs it is 5', it would go lower than if they were 6'6". 33'36 inches would put it practically at the level of my armpit as I'm 5'2 but with over half my height in leg length.

here is my link to my reveal several years ago. http://ths.gardenweb.com/discussions/3333818/my-west-bathroom-reveal-from-project-in-2013-to-2014?n=15 apparently the link in the tread to show my pics doesn't work any longer :/ I'll see what I can do to that. here is the floor with the shower pan. The Hydroban wall moisture barrier is not showing any longer, its under the shower tiles: Read the reveal text that I linked above. It will tell all about everything I used in this bath remodel: Floor with unfinished vanity, across from the shower. There are 2 doors into this room, the one you see here and on the other side of the room facing this door. Its my bathroom hallway, lol: Have to show my laundry center, across from the toilet. My beloved Miele washer and dryer:

Vertically?

Ok, that makes it tougher, but one of the better electronic stud finders might still locate the studs through the tile. I prefer to mount something that needs a lot of support - like a grab bar - only in studs. If you can locate the studs, but can't find the right length grab bar to perfectly match the stud spacing, one solution is to buy one that is slightly longer than the stud spacing and mount it at an angle that allows the ends of the grab bar and the studs to align.