Great presentation , as you said you can tow that on paper looks good , personally I don’t want to tow anything to much heavier than the tug . I think if you want to tow 3.5 ton you need one of the big yank trucks . 👍🏻👍🏻
In your example there is only 200kg of payload left before you hit the GCM. (Effectively a 3.5 tonne caravan at 350kg TBM limits the GVM to 3250, ie 6400-3150=3250) Of that 200kg left, at least 130 kg would need to go forward of the front axle (bullbar, winch, second battery, snorkel) to prevent overloading rear axle., based on a rough algorithm I followed.