if my loaded trailer is 3100, I would have to be really cautious about the tongue weight loaded, because I'll also have the weight of the hitch/WDH setup as well. 15% of that puts me at 465, and 13% is 400ish...
I don't really see me putting 800lbs in the thing but better to plan for the worst, absolutely agree. Water (sometimes), some food for me and the dogs, bedding, maybe a dog crate or two - but with the extra payload i have i can also load that stuff in the vehicle I think, as long as i can avoid overdoing the rear axle weight?