Every year I do an upgrade here or there for the truck or trailer. As the truck is starting to get long in the tooth I thought it time to give the rear springs a little support so I have ordered a set...
Who cares what your trailer weighs...or what the gross weight rating is.
What matters most is the pin weight.
May be a truck scale will shock you and find your pin weight is 3,000lbs or more. Then may be some rubber helpers like the Timbrens might help a little. But they are just "helpers". Kinda silly for these weights.
If I had a HD truck towing that amount with more sag than I like, I'd be looking at new springs or some real nice air bags.