Unfortunately this is more like a speed drawing demonstration than a tutorial. It doesn't really teach anyone how to do what you are doing.

I sped watched one of the other tutorials. You obviously have a firm grasp of using SketchUp and Extensions. My only suggestion would be the pay attention the segment number on curves, arcs and circles. In some instances you are creating denese geometry for no gain. Bezier Spline is a great tool but using 20 segments on a curve is overboard is places.