Hi, it all worked out okay so far. The ports that needed adjusting( not all of them, and some only sightly) only had the bottom adjusted. ie they were elongated. This was corrected with the external & internal planking. As the adjusted ones have linings that go all the way through, not indented by 1mm, it looks as its supposed to be and the cannons line up at the right height. Hope that makes sense. Make up a cannon on a truck and try each port ( look at cannon internal & external, remembering that a lot of it is hidden from view by the next deck, and you will be able to see what needs to be cut if needed.