As for the preasure hull, the deck has no slots in it so seeing a preasure hull would be imposible to do.Other than opening up some of the access plates on the deck. Like for loading a torpedo. But you could do a great job of scratch building and get better results. I have worked with the preasure hull resin sets for the type VII that were in resin.
With all the slots in the decks and side free flooding holes for that sub, seeing a preasure hull was not easy. The U 9 does not. Check out the Wolfpac Facebook page. I post my build progress on my U9 kit there daily.