depends on how flexible you want the ship to be. Experience from Falklands and gulf show that a gun is a flexible item in both surface and anti air role. current trends are 5in is most credible in 70's/80's 76mm thought to be enough.
Actually I am not sure about using WM-25 and STIR-180 to direct Mk.45. If it does not work, then i'll have the Oto-Melara 76/62.
Where I am up to:
-File Removed-