Bathroom Grab Bars

Recently, I posted a question about installing grab bars in my bathroom re-model. I have another question. What is the most effective place to place? I plan to use a 24 "on the wall behind the tub / shower. (This is the wall-to-back when you're in the tub.) Is it better to climb vertically as the it? This is usually the best way to install one? I need to install one on the wall adjacent to the wall with water on it. So is it better to put this bar (24 "or 32" I am not sure which) diagonally or vertically? This will be used for a bath and a shower. Also, one more thing, are the anchors for these things something that I need to put on the block I've installed between the studs before installing the drywall, or something where I install the plasterboard and then put a little lag or any other in blocking the plasterboard?

Thank you in advance.

You can sit in the bathtub to see how you can get and see where you place your hand on the wall when you go for support.

One member of my family is sitting on a bath bench, because they can not raise themselves. I place the 32 'diagonal in the tub. This let me pull and lift. Yet they are able to use it as support. The 24 "is vertically aligned with the bath. It is an area of the wall that we all touch for support.

You can add a third bar, a 24 "horizontal to the back of the tub. It can be used for lifting as well.

Grab bars anchors must be installed on the pole and can be placed after the wall panels are installed. In this way, the wall panels are not to be cut.

Home Depot has a great choice ~!