Your English is much better than my Polish, so I can't complain.

I am not familiar with that particular model and can't find the CG location. I have had a few twenty plus year old airplanes without instructions, and I've always balanced them at 25-33% down on their Mean Aerodynamic Chord with no problems.

[link=http://www.airfieldmodels.com/information_source/math_and_science_of_model_aircraft/formulas/mean_aerodynamic_chord.htm]How to find MAC.[/link]