We're doing the same thing and I haven't decided yet either. My contractor tends to like to install the elbow on the side about 3 to 4 ft above the floor. Since I see the hand held shower as something not only for the shower but also as a cleaning tool, I like to make sure the elbow is low enough so the spray end will reach those places that I will want to clean (like my self if I'm washing my hair while soaking in the tub or maybe even behind the toilet).
In my case on this bathroom, my tub is short, it is 48X32 so I don't have too far to go but still thinking. Thanks for posting.

Elphaba

Are you buying the Kohler Greek tub? I ask because 48 x 32 is unusual. I have the tub and really like it. We also use it as a shower and have a handshower in it. The handshower is mounted on a bar so that we can use it as a regular shower if we want (we have a rainhead that is used most of the time). The bar is pretty close to the corner of the tub. I posted pictures of my completed bathrooms back in 2011--not sure if you can see the handshower in the one picture of the tub.

nycbluedevil - yes it is the Kohler Greek tub. I hope to post pictures eventually, remodel still in progress for now. I remember seeing your pictures.
I got a 36 inch bar for the hand held shower and a 80 inch hose so boy howdy, this hand shower is going to take up a lot of space for such a small tub. Hope I haven't overdone it. We'll see.
p.s. I made the decision today to put the elbow to the left of the bar about 60 inches from the floor. (decision was more a guess than using serious analysis, LOL)

I think you may find that the hose is too long. Mock it up and make sure that the hose does not hang down where it would be in your way when you sit in the tub. Putting the elbow at five feet may make it ok. Mine is lower than that but I have the shorter hose. I also got the shorter bar. I debated this too. In truth, I don't think I have ever adjusted the height of the hand shower in either bathroom, although maybe we would if they were the only head.

your probably right about the hose being too long but... I want to make sure I can reach the toilet on the other side of the (very small) room. I like the fact that I can spray the bathroom floor with the handheld - an easy way to mop if I have time to wait until it dries. I've done this in my other bath and because the furniture is floating (in both), it is quite convenient.

Still can't decide what to do!!! And the plumber needs my input pretty soon. Should I center the bar for the handshower? If I do elbow 5 ft from the floor, it seems like the hose will keep hitting the valve trim.

I realize this is an old post, but just in case someone catches this... Do you like having your only shower head on a slider? I'm planning on Kohler's purist line in brushed modern brass. I definitely want a handheld shower for both our master and our kids/guest. Not sure if their handheld/slider option is durable enough (particularly the mechanism on the rod) or even if it tilts enough, to last. May need to go for their fixed head plus the slider but that just adds cost.