I see 377 lbs tongue weight on one dealer site.
That is probably dry weight.
Add the weight of a battery on the tongue, 2 full propane tanks, plus items that you put in the storage area. Also add some weight for anything that you stow in the trailer that is in front of the axles and that would include water in the tank(s).
You could easily get to 500 lbs or more on the tongue. You will need to get an accurate tongue weight - loaded, ready for travel.
600 or 700 lb spring bars would have quite a bit of force on them when loaded and if you were to use the Reese Dual Cam setup (like I do
) you should find that the setup handles very well on the road.