You also need a wall supply. Depending on the handshower you choose, you may also need a separate check valve. I was told in a showroom, that Moen puts their check valves in their handheld shower, so the wall supply doesn't have one. But, you can buy one. Hansgrohe, however, doesn't put one in their handshower, and you can buy a wall supply with or without the check valve (I believe), so you need to make sure you buy the right one. It is okay to have more than one check valve, but you want to make sure you have one.

Are you going to have a standardd shower head too? Because the benefits of having both are great. First, it's just the two of us as well and we still had the slide bar secured so it could double as a grab bar. You know just in case there's ever a slip. Then we also wanted the advantage of being able to adjust the height of the hand held. As it turns out, we can use both the slider & the shower head at the same time and boy is that wonderful! Basically with the slider you have more options for height and a secured slider can be a safety feature. Even if you don't need it now, for resale, that's a plus. I think for us it was one of those things where if you don't know you won't miss it, we did it for practical reasons more than anything else, then once it was in, we saw how great it is and were tickled pink.

There's no one correct answer regarding elevation. The slide bar should be installed at a height that makes its range functional. That can make it dependent on the highest height you want, the lowest height you want, as well as the length of the bar itself. Some folks simply want to take a traditional shower. Some want to be able to lower the head so there is no way that their head can get wet. I've had some require a height for waist-down showers. And for shaving legs, some have requested the head to be able to be lowered to a mid-thigh height. I do have to say that I prefer the shower head to be able to be raised about 8" above the height of the tallest user. If there is no "tallest user" then I shoot for the bar to be set so the head can be raised up to a generic 7' above the shower floor. As far as centering things, again, that can depend on the style of the bar, the bracket, and the head. I do prefer the head to be close to centered. It can depend on the length of the hose too. Let's say the bracket offsets the shower head to the left of the bar. I might install the sliding bar to the right of center so the head can be centered. I might install the wall outlet just to the right of the bar. That way the hose will hang down from the wall outlet, make a "U" under the bottom of the slide bar, then go upwards to connect to the handheld. But again, that's dependent on the length of the hose and the length of the bar. But that layout will allow the hose to hang in a "U" shape flush to the wall instead of the hose crossing over in front of the bar and projecting out into the shower, or getting looped over itself in a twist. Sounds like a weird point to make, but it does neaten things up. The height of the wall outlet can depend on those same things. Your configuration, the length of the hose, etc. What you don't want is your hose to snag on anything when you adjust it upwards or downwards, the location of the wall outlet can be varied to minimize the possibility of that happening. Again, it all does depend on the fixtures in the shower. The length of the bar, the length of the hose. It's easy to mock things up with tape on the wall and a piece of rope for your proposed hose length. Don't forget that the style of the handheld itself can result in the actual shower head being several inches higher than the height of the sliding bracket. Some brackets are adjustable so that the handheld can be rotated up/down on the bracket, as well as the bracket sliding up/down on the slide bar. So a sort of ambiguous reply, but there is no hard and fast rule. Example, in my own shower? I'm 6'4, my wife 5'1. I have a 40" long slide bar. I have a large shower, so I have an 8' long hose. The shower head can go from well above my head to below the height of my wife's head. The hose allows the head to reach out and touch every point within the shower for bathing or for rinsing the shower walls down if needed. Depends on what you want. Some want the head lower for kids using the shower. Lastly, you can usually by just a wall bracket that can get mounted to the wall. So you can have your handheld on a slide bar that goes up and down as needed. If you then need an out of that range height, say for shaving legs, you can mount a small wall bracket lower on the wall just for that.

agree with ravencajun that there are some really nice handhelds out there that rival or even beat a basic fixed head, plus their utility for cleaning is critical to me. Another option is to place the handheld on a slide bar so you can adjust to different heights. This is especially nice for kids or folks with very different heights. Unless you have a wide tub, I would be inclined to go with a really nice handheld on a bar and the tub spout, otherwise as linelle pointed out it will get busy with so many fixtures. Plus you will need additional diverter valves and trim for extra fixtures and you may decide that money might be better spent on upgrading the shower head (or some other part of your redo) We went all out in ours, but it is a good sized shower only - but you can see what it looks like in the picture below with two fixtures on one wall. I forget the exact dimension, but it is probably at least 40" across. Here is a link that might be useful: Master redo