tongue height

@NovaTab It is important to be level on a two axle trailer for even braking, tire wear, better handling.  Not as much on single axle trailers like ours. Too low at the coupler, and we have a slightly heavier tongue weight; too high and the tongue weight will be a little bit less. "They" say that can introduce sway due to a light tongue weight, but you'd have to be several inches too high to make a lot of difference.

The real concern is the aesthetics and the RV tow level police.  The eyes of any camper who has towed more than a month is so finely calibrated, they can tell if you're towing a millimeter too high or low.  Not really, but it's a common meme practically for the very first comment after somebody posts their brand new rig picture to see: "Why are you towing so low?"  Not on this forum of course, but on other social media.

If you have to choose, probably go with a bigger drop hitch and tow a little low. I've never heard of a coupler failing when somebody towed 6" too high and the upward force in an emergency braking situation separates the trailer and hitch. But common sense (maybe) says that's more likely.

But if you can, find the right drop or rise to get within a half inch of level.  Just to avoid folks at the campground silently going "Tsk Tsk" as you drive by.  

On my Jeep truck I had to go with a 10" drop hitch then a 1" rise on the ball to be level on the original non-boondock 320.  Looks weird, but it's level.  Your Trailhawk should only be 6" or 8" unless you've lifted it?

Not an option on the diesel. Just factory tow pkg with bigger alternator, maybe transmission cooler, and the hitch receiver w/wiring. I think I read the diesel already had the iron steering box, bigger axles, etc by default.

For the toy hauler I have an R3 adjustable sway / adjustable load weight distribution hitch, and the camper has a lifted single axle, but with an extra pair of shocks and adjustable air bags with a remote to fine tune the trailer level. More complicated than just dropping the T@B coupler on the Jeep ball and heading out, sadly. But if I was still towing the T@B it sounds like those progressive Max Tow springs would be the first swap for a smoother ride 

I usually prefer to do my own suspension swaps, preferably with a cheap $20 spring compressor, and only on one side, so you just never know what the spring will do.  More excitement and adrenaline than three cups of coffee.    

Although I think if you drop one side of the rear axle all the way, there's no tension on our Gladiator springs doing one side at a time.

Yes, the Grand Cherokee does do an auto leveling when connected to a trailer.  Makes a very nice TV.
cheers