Ah s*** - edit for short answer.
Perfect loaded.
Not too rough empty..
.....
We had -
4 adults and 1 kid along all the time, including the hitch rack, full 52 Qrt cooler and a possibles box for a 192 mile trip.
Never bottomed out, handled great and passengers had smiles all day long, even after the rides..
Mostly unimproved rocky, 2 track- horse trails, tons of water crossings and some out across the sagebrush stuff. Lots of wash outs on desert dirt roads. And a fair amount of low speed rock - climbing. Nothing really technical, but used 4wd on the off -camber slow stuff.
I did stop and let some air out of the tires. Had them pumped up anticipating the load, but was too rough.
I'm glad I spoke to some guys at a local off road shop and the sales people at Viper, who recommended the 350# springs for my application.
No more sag and now have 13.5 inches of preload with less than 3/4" spring compression.
Very happy and would do it again.
Viper was great to work with and a friend at Performance Offroad of Oregon, swapped both shock springs out for $50 bucks...hey.
Oh, and not rough empty. Could always adjust rebound, but haven’t had the need. I always have spare tire & rack, juice cans, sheepherder jack, 75 # possibles box and cooler, even solo or with with my lifetime passenger. Doesn't ride too harsh.
YMMV