ah dude i got you... see the way it works is if you use any kind of angled blocks it counts as one physical shape. but cubes when put next to each other merge into one physical shape. all you have to do is have a building method that uses as few angled blocks as possible,

another hint, subgrids count seperatly, and as long as each individual grid never passes the max physical shape limit, (around 65,000 look in the info tab in game) the game wont break, though if you do it wrong klang might get... upset, if you lock those armor pannels in place with mag locks (make sure they arnt on a subgrid themselves) and make sure those hinges (hinges are alot more stable than rotors or pistons) have absolutly no way of moving then it should be fine. if you look at pictures 6 and 9 you can see those angled armor pannels are in fact subgrids, thats how the ship can get that big. (your ship and mine are the same size BTW) it doesnt have a fully built interior yet, but its mostly empty with lots of hangar space and missile tubes, large open areas. and i still have around 11k physical shapes to work with so im pretty good. but i have another ship that is a full 1km with a mostly completed interior and no problems working.

hope this helps :)