What the Revenge-class preliminary designs traded away

What is known about the Revenge-class T1 to T4 preliminary designs?

They explored how to make an affordable 15-inch-gun fleet battleship while preserving armour, ultimately sacrificing speed.

The design problem was how to produce an affordable battleship with 15-inch guns. The designers were unwilling to sacrifice armour, so speed became the principal concession. Separate personal design studies are distinguished from the official T1 to T4 sequence. Those studies explored nine 15-inch guns in three triple turrets, with the turrets grouped together to seek higher speed at the desired cost. They are described as anticipating ideas later associated with Nelson and Rodney, F3 and G3, without making them part of the official T1 to T4 sequence.