What you are referring to as "sway bars" are not.. They are weight distribution
bars. If you are using 15K WDH (weight dist hitch) for a 6K trailer, you
prob will never get it in the sweet spot. You could sell that set and go to
a 7500 or 10,000 lb system and be way better off... Then you can decide
if you want to get a system that has the "sway" component built into it or
add it separately. Up to you on that.
I really like my set up as it has the sway and WD hitch all in one. But it was
pretty pricey.. I did the 10K system and it was like $700 a few years ago.
Equal-I-Zer is the name brand. American built.. Good stuff.
You order it by the tongue weight of your trailer. I expect the tonque weight
of your rig to around 600-800 lbs.
https://www.etrailer.com/Weight-Distribution-Hitch/Equal-i-zer/EQ90-00-1000.html
this is a link to the 1000/10,000 System. You can prob find one from a diff mfr
in the 800/8,000 for a bit cheaper. But I know this works.
My camper is 9500 lbs w 900 tongue weight going down the road.
I have made mods to accomodate this at it's way over the rating on my Yuk