What guns would the Splendid Cats carry if the Invincibles already had 14-inch weapons?
Short answerThey would probably jump to 16-inch guns because 13.5 inches is a retreat and 15 inches offers too small a visible advantage.
NotesThe political logic of a naval arms race matters more here than automatic calibre growth. A 13.5-inch battery makes no sense after a 14-inch predecessor, while 15 inches may not look like enough improvement to justify the new class. Moving to 16 inches produces the conspicuous leap expected from the Splendid Cats. An earlier heavy-gun choice can also compress later development stages. Relative signalling therefore shapes the ship alongside its technical possibilities.