The DFT has a fact sheet on on Towing Capacity, Tow Bars etc here. But that just tells you the minimum legal requirements. You will need more information to help you to match your tow car with your folding camper or trailer tent.
The Dutch Caravan Club has a free towcar matching service here. Unfortunately it lists rigid caravans but with a bit of experimentation you can find a caravan of a similar weight to you folding camper and do a check on that. This system does not just apply the 85% rule, it looks at the power of your car and predicts how good it will be in different road conditions and slope angles.
The Caravan Club (UK) has an outfit matching service for members only and also has some free information leaflets here which can be downloaded by non-members. More.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.