Well part of being an artist of this kind is that sometimes you have to just make stuff up. Don't think of it as a problem, think of it as your opportunity to add something of your own to the model. Your own mark on the model, that can be however you imagine it (within reason of course). I've had to do that with these ships a lot, because even with the BaQ ther were many parts of the side drawing that didn't match the top view, and vice versa, and there was nothing showing the bottom of the ship at all! I just had to imagine what it might look like and make it that way. This is your opportunity to do the same.
As far as the nacelles being too thin, don't worry about it. They are not supposed to be very thick. They are an all new type of nacelle that is built into the wings and ultra-thin. Just do with them what you think they should look like within the canvas of the model. I really think you should put some of your own imagination into it, you might be surprised how good it can look.