Sorry it took twelve bloody days, but life all of a sudden went crazy. This are now calm again, for the moment.
I'm afraid scaling this to real specs didn't do much good. The aircraft is very unstable and requires a lot of positive elevator to stay airborne. She's painfully slow, and can be out-accelerated by a gravel truck.
Please feel free to tinker. I will try again with AirWrench when I return home.