Ahh ya, I know it's always easy to suggest adjusting tongue weight like it's an option in every instance but ya, sometimes it's just not possible or won't make much of a difference. Sounds like you would really benefit from a wdh though. The initial set up would really be the only real inconvenience, IMO. It does take a bit of trial and error to get the angle on the ball mount height and the shank adjusted properly so that your trailer rides level when loaded. Once that's out of the way, though, the spring bars are really not that much of an inconvenience. After a while, it will just be automatic. Takes me a couple minutes to hook up.
What kinda trailer brakes? If electric, then should have no problems using wdh. Surge brakes, weeeeell, ya might have to get creative.
Do you still get a lot rear end sag when the trailer is running light? If not, as I mentioned previously, then no need to hook up the wdh in those instances. If you still want to use it when running light, you could always just add some ballast to the front of the trailer to add some some tongue weight (tw)... may be a full tool box or I mount a spare tire on my tongue (or both). You could also go down a couple links on the chain so you're not ratcheting it on to its most rigid setting. And you only have the spring bars connected when towing. When not towing, you just have your hitch (and drawbar, shank, ball if you decide to leave them) so no need to worry about riding jacked up when not towing.
It is important to know what your varying tongue weights are though. There is no getting around that. wdh are rated by tw. If you buy one rated too high, you risk bending your hitch receiver. Buy one too low and you don't get the full benefits of a wdh. You might have to do a little bit of research but I'm sure you can find something that will work for you.
The other option would be to move the axles of your trailer forward but that may be another one of those easy suggestions to make but not really practical or feasible.
