Would alternate Nelsons keep 16-inch guns?

Would Nelson and Rodney use three triple 15-inch turrets and make about 26 knots in this treaty system?

Probably not: the extra displacement could produce roughly 28 knots while retaining their 16-inch guns.

A roughly 40,000-ton limit gives Nelson's designers four to five thousand more tons than the historical ships. That margin can support the machinery needed for about 28 knots while retaining the 16-inch guns. The historical calibre choice is described as partly driven by treaty prestige. A voluntary reduction to 15 inches is therefore less likely in a settlement that already permits the larger weapon.