What a wonderful 'documentary'! I was at the 1000-km. race there in 1964 when a Shelby Cobra won the GT class for the first time. During practice, one of the Porsche 904s failed to come around, and Porsche's racing boss, Huschke von Hanstein, took me around the whole circuit in his personal car (a 356 Carrera coupe), trying to find his lost race car. "Look for holes in the hedges," he told me. So your hedges look perfectly authentic to me (I love the fact that they're not hard-edged, but more like rose bushes, as in real life), as do the wooden-pole fences and the curious, below-ground-level paddock. I also appreciate the other layouts (like the Sudschleife and the Gesamtstrecke), but wasn't the S/F line straight much, much wider? I had some good times in the Sporthotel watching eight cars abreast at the beginning of the race.
Cheers!