Hi Paul, lit portholes ? well you are going the whole hog, I would personally use 6 volt led's they have a much longer life than filament bulbs and run without any heat, plus less power drain and one tip if I may, use orange ones they look far more realistic on a model than clear white light I used them on my railway buildings with good effect, Do you intend to switch the lights remotely, this is how I did the lights and smoke on my paddle tug.