How an earlier King George V design would change the main battery

What would be different about a King George V-class battleship begun in 1931?

It would probably carry nine 15- or 16-inch guns; the historical 14-inch battery would be unlikely to win an earlier design contest.

An earlier design would probably carry nine 15- or 16-inch guns instead of the historical 14-inch armament. Treaty timing and procurement politics shaped gun choice, so moving the decision into 1931 changes the assumptions before detailed naval architecture begins.