I have a hybrid kit on my big XJ. RE 7.5 coils front, t&t long arms, rusty’s 6.5 rear leafs JKS shackles, and RockKrawler shocks. My little XJ has rusty’s 4.5" coils, bastard pack rear, 1 ton over load spring that only contacts the leafs when the trailers weight is on the rig, and gas shock all around that were set up taking into account the load of the trailer (I built this jeep to pull this trailer so I could still work when I brake the other XJ). I tow a mid size trailer (Good 500 lbs+ tongue weight). I probably drive an average of 55 miles a day w/ the trailer for work. As long as the sway bars are hooked up they both tow like champs. I feel safe going 70 mph on the freeway with the trailer (not that I do, other than passing) Youll definitely want the bigger brake booster for added stopping power, junk yard disc brake will do wonders for you too. Make sure your geared right for your tires size too.
I have not had any problems with sagging or anything like that either. Other then lack of stopping power on stock brakes never had any other kind of problem. My jeeps handle just fine w/ a trailer behind them.