Claude
The two Type VII's were a joy to build. Everything fell together like a puzzle. The decks are really nice and have very tight joints. I would not use the rigging string provided in the kit, its too thick and fuzzy. I used 'Wonder Invisible Thread' smoke grey in color, and very thin. This is available at any craft store for under $2. The decals are of high quality and are very well done.
This is how I did the drilling in my Type VII's. While the hull halves were separated, I thinned out the plastic on the inside to make the drilling and cleaning easier. I used my dremel with one of the many abrasive wheels and set it at a low speed to keep the plastic from melting. I then used a drill bit size slightlty smaller than the flood hole on my drill set at low speed and drilled on both front and rear of the flood hole. I then took the Xacto with a new sharp #11 blade and carefully cleaned out the flood holes. Then I used my needle files to carefully smooth everything. After joining the hull halves, I used a piece of thin cardboard and secured it on the center of the hull, meeting the bottom of the deck. This takes a little patience until you get the angles which do not have to be perfect in there. I then sprayed the inside of the hull and the cardboard flat black. This will not let you see thru the hull but still provide the benefit of the drilled effect on the flood holes. I sold both U-Boats so I don't have any pictures to post to show you how the final products ended up. I did this to keep cost to a minimum. There are so many aftermarket and PE sets out there that you will spend more for these parts than the original price of the model.
Division 6 posted some good info on the conning tower details. Wow, I thought I detailed this area on my boats but that's really a work of art, specially the railing.