That is true but i personaly find it stilly that artillery can't sink ship i mean common! there's many example of that in ww1 and ww2 i belive, yep its usualy ship guns vs ship guns but those ship guns are powerful ive heard they can go up to 23 km or so... and many ships was destroyed by that so....
its not cheating, its true, i always turn lethal bombardment for my airplanes, not the airplane but for the bombers, i mean look at pearl harbor in ww2 the jap drouped torpedo/bomb on the ship, pretty much destroyed em then they dived into em, to me that is what lethal bombardment is.
then on cannon and stuff its little ify but if you think about it many wood ships has been put to the bottom of the sea by cannons, so its really up to you but i usualy have lethal bombardment on cannon, artillery, radar artillery, cruise missiles, then most ship newer than the gallery. and so on. don't forget the bombers.
and you do not need to setup ur more serienco, you just need to make a backup of the master file, and edit that. that's what the mods out there do, they edit master file which pretty much everything else is based off and if the serico dosen't already have their custom rules then they will get it from the master files.