Okay, I was just curious. And I agree, I think a perfectly accurate Hogwarts would be nearly impossible! But, I'm also one of those people that has the basic layout of the castle (in the films) committed to memory. I have a few video-games from a few years ago that show an accurate layout, so that is how I'll be doing mine...for the most part!
I don't know I'll just try to best fit each space, so some interiors won't be where there supposed to be. I think I'v already started with the library as I'v put that above the main entrance. I think it would be very difficult to build an entirely accurate internal/external model. but then again I'm no expert I just build what I think looks good.
to anyone trying this you'll find the use of a rubber band to hold the top of the cone in compression a great help. this can be removed as in 2 of my cones or left in place as in the first one, I must be honest it's a hair band of my daughter's it's black and very fine. I did use a grey lego one with the first one but after 2 failed orders for a black one on bricklink I just started looking around the house.