Pitroad makes a decal sheet called DP-1 which will have the hull and island numerals, some deck markings. StarFighter Decal also makes a sheet for LHDs which you may find useful for deck markings. Unfortunately if you doing the Dragon Saipan most of the helo Vs and the dotted white lines have to been done with either fine paint pen, colored pencil or paint brush.
Did the Saipan years ago. Those deck markings what a bear!