Variables to consider include the size of your planned field tiles including grout width as well as.
Tile half wall height.
The minimum should be 6 feet from the base.
Tile half wall height how to finish the top other than bullnose.
I have seen it done as a fully tiled wall but ours will be only half way up.
Much depends on your taste how tall the shower head is and whether you want extra protection from mold or potential splashes on the paint that could eventually cause problems.
I believe your title or question answers it s self.
For a truly classic look finish the top with a decorative trim or a bullnosed edge.
I prefer at least 6 and a half to 7 feet.
The classic design feature is usually between 34 and 54 high with 36 being the average height.
How high to tile when tiling half the wall.
A classic offset or straight set pattern in a standard field size tile works best for this wall height.
A practical height when working with full sized 12 tiles is 6 courses.
Half the wall is half the wall.
Calculate your ideal height for the half wall which typically ranges between 30 to 40 inches.
Factoring in the grout lines this meets the minimum with a bit to spare.
If your wall is 96 then 48 is half.