Why treaty battleships studied 16-inch twin turrets

Why did the Royal Navy study 16-inch twin turrets in the 1920s if triples were more efficient?

Twins allowed a slimmer beam under treaty limits, trading extra length and machinery for a hull shape that could meet the displacement constraint.

At very large calibers, three triple turrets generally save weight and provide nine guns compared with the barbettes and machinery required for four twin turrets carrying eight. Treaty studies nevertheless used twins when designers needed a narrower beam and could exploit extra hull length. Without the 35,000-ton constraint, the broader and more efficient triple arrangement became easier to justify, as in later Lion-class thinking.