Treaty tonnage for a Royal Navy three-fleet system

What capital-ship tonnage limits would support a Royal Navy three-fleet standard under Washington-style ratios?

The rough calculation gives Britain and the United States about 650,000 tons each, Japan about 420,000, and France and Italy about 250,000 apiece, enough for a British minimum of roughly twenty capital ships.

The treaty ratios yield approximately 650,000 capital-ship tons for Britain and the United States, 420,000 for Japan, and 250,000 each for France and Italy. Twenty British ships form the bare minimum for three principal fleets, while 15-inch-gun designs averaging about 31,000 tons could stretch the allowance to twenty-one hulls.