WE must consult form a bathroom renovator or bathtub or shower installer about this query as the are experience in this according to me there are design guides that deal with it.
I just installed disable baths and showers and the used shower and that should all be above 6 ft. Or that is good for all. Or rest all are depend upon the client requirement it should be 5 to 6 ft only.
Now-a-days, Various models are available in Shower heads also. They are in 1/2 In. Connection size, Hose length (in.) is 72. Like that many more specification is there. AS per our need and interest we have selected the best ones.