From the Photo, the max ball weight is 10% of the gross towing weight.
So, for a 350kg (gross) trailer, the max ball weight would be 35kg.
I understand 350kg is the max weight for a "Light" towing category.
Edit: A little more information.
The manual for my new Jimny has a good section on towing.
The max un-braked trailer weight: 350kg
Ball weight from min 25 to max 75kg, they suggest measuring this using bathroom scales.
(They must have big bathrooms in Japan!)
Last edited by gclark8; 02-16-2019 at 05:27 PM.
Reason: Bathroom Scales!