Maybe i am blind but why arent you using the robson drive on the trailer? I myself use a small Valtra with a 9-tonne trailer, have chains on the back wheels for steep hills. Works fine for small scale. In these conditions i would prefer a mini forwarder with tracks like Alstor 840. But i guess you have to use what you got.
Sveikas, nepamenu, kad ką nors būtų sulaužusios grandinės, bet paliksiu operatoriaus dirbusio su šia valtra numerį, skambtelkit darbo laiku, gal smulkiau papasakos😉 Giedrius +37061803968