Fortunately the rudder work is do-able while on meds for what is now officially a ruptured disk in my upper back.
The plans are less than obvious, so some points here may help others. I made the stiffener ribs, which starts with cutting 8 pieces of pr-drilled angle in half, then putting a taper in each of the 16 angles that result. The plans are not intuitive...
Each piece has some small half holes that are markers for where to draw a straight line and then trim the angles down. This is not mentioned in the instructions. I trimmed all pieces like this, then cut them to length by matching them up with various locations on the rudder skins. Ignore references to "from the front" in the instructions. I still have absolutely no idea what that reference is to (front of what?).
Also not mentioned is that you don't need to worry about which way is "up" for the stiffeners. They will only fit one way.
Not mentioned is that you need to flute the stiffeners, in order that they will lay flat and not distort the rudder shape.
Others say to use ProSeal when attaching, in order to prevent cracking in the skin later. Guess that it's time to order some -- or maybe I'll just use some RTV, since I already have it.
Have seen all sorts of crazy ways to cut down the stiffeners; however I simply used a pair of straight tin ships -- the old kind, without serrated blades. Don't forget to cut the butt end of the stiffeners at an angle (not square), in order that they won't interfere with the rudder spar when assembled.
It is hard to believe, but what you see in the photos below represents over 4 hours of work. Lot of that is belt sander and debur work on the edges. I went backs over each piece to make certain that the taper has a clean and straight run.
Time: 4 hours