An alternate treaty split between six-inch and nine-inch cruisers

Who would gain or lose from treaty limits of 8,000 tons for six-inch cruisers and 16,000 tons for nine-inch cruisers?

The Royal Navy would probably benefit most, Japan could build strong ships more openly, and no power is an obvious decisive loser.

The Royal Navy would probably benefit most from the proposed two-tier cruiser limits. Japan might also find it easier to produce powerful ships without relying on the extreme under-declaration associated with some historical designs. A nine-inch cruiser would need substantial armour as well as larger guns before it gained a convincing advantage over a 16,000-ton six-inch ship. The treaty would change design incentives without creating an obvious single loser.