Why a large cruiser benefited from 9.2-inch guns

Would twin 8-inch guns have been preferable to the Edgar class's single 9.2-inch guns?

No; twin 9.2-inch guns would offer heavier impact with little rate-of-fire penalty and give the cruiser greater deterrent power.

An audience question asks whether twin 8-inch mountings would have been preferable to the Edgars' single 9.2-inch chase guns. The preferred alternative is twin 9.2-inch mountings because the rate-of-fire difference was small relative to the heavier shell's effect. The large gun forced smaller cruisers and larger warships alike to account for the threat before closing. Like a torpedo tube, it could shape an opponent's choices even when it did not fire.