Some Beginner questions (weights, trailer length, etc.)

hitch capacity or payload will be the bigger issue more than the trailer weight, for the Range Rover.
also, with that short of a wheelbase, look at a Hensley or ProPride WDH.
and don't make the newbie mistake of believing brochure/website "dry" weight numbers. those are only for a stripped-down trailer and not real world numbers.
start with the trailer's yellow weight sticker number. that's a much better number to start with.

You need to know more about your trucks capabilities than just my truck can tow x lbs. (I learned this the hard way). Most TV are limited by their payload. To find out your TVs true towing capacities then you need to go weigh it. Load the tv up with all occupants, pets, and cargo that will be in it when towing plus a full tank of fuel and then go weigh it at a local scale (www.catscale.com). Weigh each axle on a separate scale pad so it will give you a breakdown of front and rear axle weights individually and a total weight. Take the total weight and subtract it from your Trucks gvwr to get your available payload. Take the scaled Truck weight and subtract it from your Truck gcwr to get your adjusted towng capacity. Not owning the truck, you can look at the sticker inside the drivers door. It should say "occupants and cargo not to exceed x lbs". take the weight and subtract the weight of you, any passengers and pets plus any gear you plan to have in the truck when towing. The number left is a rough estimate of your available payload. You need a loaded tongue weight less than this number.

Now understand you will never tow an unloaded or dry trailer. Those numbers are somewhat irrelevant. You can either add the amount of weight of cargo you will tow to the dry weight (this is heavier than you think as most add 1000-1500 lb of gear) or simply use the tt gvwr to do your calculations. (for your purposes do all weight calculations using TT gvwr). Next understand that the tt loaded tongue weight needs to be subtracted from your available payload. The loaded tongue weight is typically 13-15% of the loaded tt weight. The dry tongue weight doesn't even include propane or battery. Also anything placed in the trailer in front of the axles will add to your tongue weight. For your purposes 13-15% of the TT gvwr will be an easier calculation to figure out.

An example here (totally made up numbers from fictional vehicle).... curb weight on scale loaded with passengers and gear: 8500 lbs. TV gvwr 10000 lbs. you have 1500 lbs available payload for a loaded tongue weight. On the fictional trailer, there is a dry weight of 5700 lbs and gvwr of 7700 lbs. Said trailer actually scales in at 7000 lbs loaded. 15% of the loaded (7000 lbs) weight is 1050 lbs. Fictional truck may also have a door sticker that says occupants not to exceed 1700 lbs but with pets, passengers and gear you are down to 1500 lbs available payload.

Just an fyi, the brochure dry weight on my tt was listed as 6800. The yellow sticker on the trailer as optioned is actually 7400. Big difference, don't trust advertised weight if it's gonna be a close call.

SUVs tend to have it rough because lots of folks buy them to haul family, which can eat up that 1700 payload a bit. I know there's folks on here that tow with RRs, so I'll let them speak on that, but you are correct in that the tongue weight of the trailer and weight of the hitch will subtract from the payload. Keep in mind that the tongue weight for a properly balanced trailer is usually between 12-15% of the total weight of the trailer. Brochure dry hitch weights don't give a good picture of what your actual tongue weight will be because they don't include options on the trailer, propane in the tanks, or even the battery sometimes.

Good luck in your search! :)