Why use 16.5-inch guns on the German super-battleship?

Why does the German 90,000-ton design use 16.5-inch guns in quadruple turrets?

The caliber is linked to remembered H-class studies, while the game model's oversized twin 18-inch and 20-inch mounts drive the quadruple 16.5-inch layout.

The 16.5-inch caliber is linked from memory to German H41 or H42 studies. Twin 18-inch and 20-inch weapons were considered for the game design because German studies also explored larger guns. Their turret models are judged excessively bulky in Ultimate Admiral: Dreadnoughts. The chosen solution enlarges the game's 16-inch gun to 16.5 inches and uses sixteen barrels in quadruple mounts. The caliber has a remembered historical inspiration, while the final turret arrangement responds to the available game models.