I've never seen a vehicle spec that listed tongue weight. Are you sure you are reading that right?
The tongue weight of your trailer is part of the cargo of the vehicle. So your vehicle cargo weight less the tongue weight of the trailer, has to leave room for people and other stuff.
The cargo van probably has a stiffer suspension than the passenger van, thus the higher towing capacity. Towing capacity is not the same as pulling power!
The tongue weight of the trailer will depend on how much you put in it, and how the contents are arranged. Any water you carry is part of the trailer cargo, too. The only reliable way to get an accurate tongue weight is to weigh the trailer as loaded.
For good towing characteristics, the trailer should be loaded so that the tongue weight is 10-15% of the total trailer weight. And most of the time that's achieved with a little common sense. Don't put your heaviest stuff in the back of the trailer.
I'm looking at the NV3500 passenger specs here.Your vehicle is listed with 2460 lb payload. The tongue weight of the trailer is part of that payload.
Towing capacity of your vehicle is listed at 8700 lb with the addition of a class IV receiver. If you look for a trailer no more than 80% of that, about 7000 lb, (a good guideline) your tongue weight of the empty trailer will be 700-1000 lb, plus add another 100 lb or so of tongue weight for contents of the trailer. So at 1100 lb tongue weight MAX you will have 1300 lb of cargo capacity left for people and stuff.
You should be able to find a nice trailer in the 5000 lb range, and that's what I would stick with in your shoes. You will also want a good weight distributing hitch like an Equalizer. Don't push the limits of your vehicle and you will be much happier.
