I must urge caution when using some of these 3rd party sites.
with the bets will in the world, these sites rely on humans to input the data about makes and models. There have been some errors identified with some model information, resulting in erroneous recommendations.
As most caravanner's tend to use up as much of the weight capacities they have, it is easy to exceed limits that have legal implications on your outfit.
It is always best advice to check your weight and load limits with the data plates on your car/caravan, or the dealer or the manufacture.