How do you know it only weighs 1000 lbs? Scale? Or 'paper'?
The tongue weight
should be 10-12% of the actual total weight. So, if you weigh the axle
and tongue jack weight on a scale, loaded for the road, and it all weighs 1000 lbs, then 100-120 lbs of that should be on the tongue.
OTOH. if you are using 'paper' weights (Manf brochure, frame tag, title
, etc.) and it really weighs 1,500 lbs loaded, then TW should be 150-180 lbs. My 91S13 weighs 1,700 loaded for the road.
on the tongue is a setup for sway; err on the heavy side.