I want to make a building the size of the Winterhold entrance area in a grassy field surrounded by low hills and trees. You will not be able to leave it just look out the windows. Should I choose small world or fixed size and if so how big? I'm not really sure of the relation between the size of the cells and building size. Since you are unable to leave the building or see anything other than sky past the hills how many cells would I need?

I've been watching some videos and playing around in a test mod but not very sucessfully. Any advice for such a world like which options I should choose would be appreciated.