It is a little different for us self builders as we are or should be in control of the weight although too many aren't. Our self build on a new LWB Crafter was getting heavy. I made the mistake of not weighing it from new and using VW's spec which said 2065-2450 and assuming the middle. Shortly before completion I put it on the weigh bridge and it came out at 3250. I have since had it re-plated to 3900 (sum of both axles from the factory) and now ready to go with fuel, water, tables, chairs, screens and so on it goes 3450 which allows 450 kilos for me and her, the dog and occasional bikes. I also had air assist fitted which helps the rear suspension and gives it a stance more akin to an empty van. I have heard stories of people with extra long extra high vans looking for conversions but they have a payload of a sack of spuds.