Seems pretty reasonable to me. I have concerns about blast damage on all of the light AA, but maybe that's just the price you pay sometimes.
That exactly why I raised the 5"/38s above the deck. I looked at the Iowa class and saw what they did to avoid blast damage. Low and behold their 5"/38s were on pedestals one deck above the light AA. In an anti-aircraft role with the muzzels ponting skyward this might have made allof the difference, on a ship to ship/shore bombardment who knows but the poor sods manning the 20mms.