And here it is working in flight!
And finally, a video, first showing the rudder working close-up, and then showing the kite flying with a working rudder.
In case you're wondering: as far as I can tell, the rudder does not have a major effect on the control of the kite. Flying a Target Kite with rudder didn't feel very different to me compared to flying one without. Can't say I'm very surprised about this, as the steering is mostly by pulling on one wing or the other, and the effect of the little piece of plastic on the tail of the kite is bound to be small. And you may have noted that on my kite the rudder is larger relative to the keel than on the original Target Kite ... Did it really have a significant role in steering the original Garber Target Kite??
So what's next? Make another keel + rudder for the Target:FW kite, and the Target Kite project is completed!