The game is NOT VERY REALISTIC and VERY ARCADE right now anyway. If it is going to be arcade then it should be easy to understand. If it is going to be realistic, then it needs to model armor in a 3D, layered, manner with tapering belts, canted belts, splinter decks, etc. -- more like World of Warships model the ships and their armor design (not that that game is not arcade BTW, just that it is more sophisticated in the armor modelling. Not sure that is practical given that this game is about design ships on the fly on canned designs.Currently an All-or-Nothing or Turtle back scheme is simply a percentage modifier to armor weight for a certain thickness which is BULLSHIT. They behave VERY differently in real life with the latter being optimized for close range direct fire. If it is going to be simple, then make it simple. Besides, historically, proofing against 14" guns does actually require about 14" of steel or thinner belts which are angled to be about 14" given the trajectory within the range of immunity. The Iowa for instance has 12.1" internal belts angled to be proof against 14" and arguably 15" weapons, but not it's own 16" main battery.
Right now, the Displacement of the hulls and designs are total Bullshit and not period accurate by a factor of two or three. Before 1936 everything should be more or less capped at 36,000 tons -- treaty battleships forces interesting and realistic compromises!