How a surviving Bayern could change Scharnhorst's armament

If SMS Bayern had survived Scapa Flow and returned to Germany, how might she have affected the Scharnhorst-class design?

Access to an existing 15-inch gun could accelerate a heavier armament, with either six or potentially nine guns and a corresponding response from rival navies.

The premise returns an unscuttled SMS Bayern to Germany, leaving a working 15-inch gun available for further development. That could give the Scharnhorst designers a larger weapon sooner. Twin mountings would suggest six guns, while a developed triple mounting raises the possibility of nine. The consequences would extend to British, French, and American battleship designs, particularly if a nine-gun German ship challenged the apparent superiority of a ten-gun 14-inch opponent.