Hello everybody,
thank you for your kind and encouraging comments!
I am back with slight progress, I finished sanding and filing of the wings and tail ribs and made wheels. The first layer of surfacer showed several spots to take care of but all in all it looks quite fine. Next step will be detailing on the upper wing (ailerons, openings in the upper wing for aileron controls etc.).
The fuselage also got the first surfacer coat, turned out quite satisfactory as well.