Why smaller dual-purpose guns suited carriers better

Were Lexington's 8-inch guns preferable to Graf Zeppelin's broadside 6-inch battery?

Neither was ideal; more 5-inch or 4.5-inch dual-purpose guns would have been more useful on an aircraft carrier.

Neither Lexington's 8-inch guns nor Graf Zeppelin's broadside 6-inch armament is preferred. More 5-inch or 4.5-inch weapons would perform useful dual-purpose work without consuming the same deck, magazine, and crew resources. Replacing Lexington's battery with twin 5-inch/38 mounts would also use an established production weapon. A bespoke triple mounting would offer less value if it delayed the ship.