I think the key thing here is that to be safe and also extend the life of your tow vehicles you must do a couple things.
First check your tow vehicles manual regarding use of Weight Distributing hitches. It may be that you are allowed to use them, but you may not be. Almost all solid frame vehicles will allow it, and some unibody/uniframe vehicles will as well. Some unibody/uniframe vehicles will not allow it however.
Next check your tow vehicle's towing specs as equipped. If you are over on the tongue weight for the hitch, you'll likely have to upgrade the hitch staying within the factory recommendations for a larger/heavier hitch.
If you upgrade the hitch, then consider whether you need a WDH system. The best way to do this is to hitch up and go to the closest scales with your trailer. It can be dry (or unloaded) for this step if necessary. See what the axle weights are for your front axle, rear axle and trailer axle. Then weight the trailer by itself. The weight of the trailer less the axle weight of the trailer when hitched up is your tongue weight.
Check your axle weight ratings (in your driver's side door panel on the tow vehicle). If you are over, at or very near the axle weight ratings, you need to consider WDH.
Alternatively, you can 'guess' if things are amiss by measuring drop and rise in the rear and front axles. Measure how much drop you get from unhitched to hitched in the rear. At the same time measure the rise in the front axle both unhitched and hitched. This is done by measuring from the top of the wheel opening to the ground. If you are getting any rise at all in the front axle that is not good. However a small bit isn't a worry (1/4" to say 1/2"). With a properly setup WDH you will get some sag in both the rear and front axles versus lots of sag in the rear and some lift in the front.
Choose a WDH setup that is slightly more than your gross trailer weight. For the A-Frames the Reese 66065 10,000GTW / 600TongeWeight(TW) is a good option. Too heavy a setup will not help and likely cause undue stresses and rough ride. You will have to have a 2" receiver to accommodate a WDH setup.
You likely won't need sway control in your WDH. These A-Frames tow like a dream. Just don't load heavy in the rear to reduce tongue weight. Getting less than 10-15% of your gross trailer weight on the tongue will cause sway but as setup the tongue weights of the A-Frames tends to fall very close to the 15% range making them tow very well.
That's how I would approach it - your mileage may vary. There are some great threads about WDH over in the towing section.
2011 FR Rockwood Premiere A126 Hard Side
TV=2011 Jeep Wrangler Sahara 2 Dr
Reese 66065 WDH, Curt WDH Shank #17120
Prodigy P2 Brake Controller, Mopar 7-pin Harness
B&M Transmission Cooler (#70268)