If treaty powers had to buy capital ships from one another

If a naval treaty required every signatory to buy one capital ship from each other power, what would they order and how well would the ships be built?

The ships would be built carefully for national prestige, while buyers would choose foreign carriers or battleships that best filled gaps in their own fleets.

The scenario places compulsory purchases around 1922-23, when the signatories had very different building programmes. National prestige would encourage each supplier to build its exports well. Nelson is the expected British choice, while Italy offers Francesco Caracciolo and France a proposed battlecruiser derived from Lyon. Britain and Japan could favour Lexington carriers from the United States; France and Italy could instead use Colorado-class battleships. Amagi carrier conversions would also interest Britain and the United States. France and Italy might choose Nagato because it would join Nelson and Colorado in a force built around 16-inch guns. The different preferences follow the fleets buyers already possess and the doctrine the new ships must fit.