I think you may have got that to do list in the wrong order. Otherwise you may waste a lot of money.![]()
I agree. Take the van to a weighbridge and get the front & rear axles weighed separately. If you intend to travel with a full tank of fresh water, add water.
Then, you can do a simple calculation to determine the extra load on the rear axle. All you need is the manufacturers scooter weight, distance scooter is located behind the rear axle and the wheelbase of the van.
If you want to improve the rear axle payload you could always remove the slide-out rear scooter rack and sell it for a nice profit. That probably weighs at least 50kg.