I think that 4 matches the age the best, but that maybe the top would have to be flattened so as to be accesible from all sides.
for the sake of realism, though...wouldn't you walk around anyway so the book is facing the right way? I know that you can use a book jsut as well from the side, you can still touch the panel and all, but when you click the book in-game and it shows you the book up close, wouldnt it (realistically) have to rotate the book to the same angle? I think that a sloped pedastle like that works and works well.
about 8. While it does look nice, it doesn't really match the syle of the age, which I percieve as very geometric and planned. 8 looks too natural for me to be a linking book pedastle to ahra.