Shower tile layout suggestions
I would go with your 2nd option. Columns E and F in the spread sheet. and i would use a bull nose edged tile. I. E. a tile that is designed to have the edge exposed. Other wise you will see the unfinished edge. 

This is more aesthetically pleasing and will not put a grout line at the edge that would collect water and not let it flow over the edge of the tile.