When you cover the top you are also wanting to cover each side of the Fin as well. I would do as the directions suggest and cover in those steps. If you cover it correctly you will have a nice filet from the fuse to the fin. This area can be a bear to get right. I prefer using Sig Koverall fabric which makes the job much easier. I am attaching a pic of the tail of my 1/4 scale cub after the fabric and stitching has been applied, it will show you how this area should look.
Anthony