How a larger treaty limit would reshape Yamato

What would the Yamato class look like if treaty powers had built 42,000-ton 16-inch battleships?

Japan would need vastly larger and more demanding ships to regain a margin, or might shift resources toward large carriers and a different battle-fleet concept.

In this interpretation, Japan could not preserve a decisive margin with only a modest change to Yamato. Matching a world already fielding numerous 42,000-ton, 16-inch battleships might require a ship thirty to forty percent larger, perhaps with twelve 18-inch guns, and therefore much larger docks and industrial investment. Even several such battleships might fail to restore Japan's desired numerical advantage against expanding British and American fleets. The pressure could instead push Japan toward very large carriers for long-range interception and a shorter-ranged battle line optimized to absorb punishment.