Since you are worried about the height of the cedars, I would try "topping' a few of them to 6' to slow their growth. While I have never tried it - we just let cedars go since we don't have that many - you sure won't kill them by removing the top. The few we have grow like weeds . You can always take the topped ones out later if you don't like the results; that's better than being sorry later that you removed them.