AD simply cannot armor.
But to adress what was said about O2 (EBB version or not).
Because a ship can mount the armor to bounce semi-efficiently doesn't mean its a good idea to run it that way.
Ask yourself what sacrifice you must make in order for it to work, namely speed and firepower wise, versus the advantage you get from it. And also, is the ship designed to be efficient that way?
Cutting any firepower to KM, and speed to keep the range is a bad idea, no exception. While O2 has a decent salvo for a KM ship, its still a KM ship. Cutting a third of it makes it quite a lighthitter, and if you cut out the speed, you cut out any decent rushing option. Also, Yammy, Monty, Stalingrad, SY and L2 will probably still cut through like butter, with HE. Good luck dodging with the speed.
When we say a nation does not armor well, its not only a displacement statement, but a ship efficient one. Of all the nation, only UK ship can armor correctly AND retain enough firepower to stay competitive, without the speed getting TOO low.
Past that, you are free to play your ship however you like. You are also free to be no-lube hardcore violated by any idiot with a BB5 around, that won't even notice you had armor on. And we are free to laugh at your ship setup when you fail, and its a contributive cause to your visit to the seafloor.