From our 2003 GMC Sierra 2500HD, crew cab, short box, 4WD, Diesel manual, page 4-75:
Maximum trailer weight = 14,700 lbs (limited to 12,000 lbs with weight distributing hitch)
GCWR = 22,000 lbs
Then in the GMC manuals notes: "Tongue weight should be 10 to 15% of the trailer weight up to 1500
We have the factory installed hitch.
Using the Classic's 8700 GVWR, I am at 11.5%, which is right in the GMC recommended tongue weights. 15% is 1305 lbs.
The Hensley hitch manual lists 10,000 lbs gross trailer weight rating and 1,300 lb.max tongue weight rating.
What chain link do I adjust? Should I back off the Hensley's spring bar jacks a bit? We set them between the top two notches.