I don't think you are showing the top where the return needs to be. The reason for the code is so the end of the railing isn't open where clothing or something else could get caught. All that is necessary is to cut a 45 on the end of the rail and return a short piece to the wall. The 45 can be cut with the rail bottom flat on the miter saw table. If you want to level the rail at the top before returning to the wall. you have to calculate the angles according to what exists. You can use a sliding T-bevel, one leg on the rail, then level the other leg. This is the total angle and you need to bisect this equally, check it with a protractor. Just remember, the miter saw is 0 degrees, when set to 90 degrees according to the protractor. Looks like you have that figured out where you leveled the rail on the winder, top is the same but opposite, long point on the top. The cut would be made on the miter saw with the flat bottom of the rail against the fence. You still need to return to the wall as stated before.
Last edited by Hammer1; 04-08-2014 at 02:56 PM.