It is actually dependent upon your preference, and or how many seams you can live with. My preference is to glue the stab and the fin in place, then cover the just angles below above the stab and to the sides of the fin with 1" strips of covering that have been creased. Then I cover the sides and fill in the gaps (between angle strips) with one piece per side, which meet at the top. I am sure there are better ways, however this is only my preference.

In your case, I would glue in the already covered stab (remembering to remove the covering where the stab meets the fuse), then cover the fin, then cover both sides including any fill between the stab and fin, if that makes sense.