Thank you mate!
Pébéo varnishes are acrylic varnish (gloss or matt) that can be found in art shop in France and Belgium. Hope you can find it in Serbia because there are really excellent. You can dilute them at 50% with Tamiya thinner (or methanol) and they spray easily with the airbrush. Of course you can also paintbrush them.
Since I've discovered those varnish, I don't use other nor klir...