The stiffeners come in aluminum angle hardware. The first thing to do is "connect the punchmarks" and cut along these lines.

There are 2 stiffeners on one of each strip of hardware. Also make sure, you don't mistake the rudder stiffener hardware with the stiffeners for the elevators, which will be used later on...

We used aicraft tin-snips to cut the shape roughly..

Then each stiffener will have to be cut to its correct length. Depending on which position on the rudder skin it will end up.

The end result... 2 of each of course, they will be riveted on the inside of each rudder skin. This has to be done before the buildup of the rudder can be completed as the skins would be way too weak otherwise...

The stiffeners are then match-drilled to the skins.

And finally dimpled... Now they will yet have to be scotch-brited before the primer will stick onto them... Same goes for the rivet line on the skin.