Well, I know the Atlantas were so effective that they dropped the wing turrets(
), since they were strong enough without them(and somewhat top-heavy with them).
The Didos suffered from having a main gun whose DP-function was on a more teoretical that practical level(then again, this is true for most WW-era DP except the 5"/38 Mk.12), but served well nonetheless, to my knowledge.
The real thing that's going to matter is if the main guns are truly capable of dishing out anti-air fire. If they are, a pair of CLA would indeed be a good addition to Seiran's navy.