Why anti-aircraft refits are not just a deck-space problem

How much light anti-aircraft armament could a capital ship receive in a 1942 refit?

Potentially several heavy multiple mounts and many 20 mm guns, but ammunition storage and the extra crew would set the practical limit.

A ship the size of Hood could physically accept several octuple 40 mm mounts and many 20 mm Oerlikons. The weapons themselves were light relative to capital-ship displacement. Their ammunition, ready-use supply, handling routes, and operators created the more important burden. Any credible refit must account for that whole support system instead of counting empty deck positions.