This is a preliminary design for the Super-Yamato class, and it also largely my guesstimate.
Armament: 8 X 20.1"/45 (510mm L/45) Type 98 Arrangement: 2-2-A-2-2
Secondary,tertiary and AA: same as the previous designs
Armor: Immunity between 21,800-32,800 yards (20-30km) against 20.1" shells
Propulsion: mixed diesel+turbines, speed: ~28knots
For technical datas and more details on this ship please see: Super-Yamato class on warships1.com