Re: SWAYING
A friend and I had a conversation about 20" rim and tires yesterday. This is what we have learned frompast experience. (1) The tires that you plan on towing with, need a high ply sidewall count on them. Minimum of 8 ply (Class D), I would think for your size of TT you should be fine with that. If the profile of the tire is too short. you could possibly blow a tire or damage a rim if you get into an unexpected pot hole or rut. I would make sure that you have a good profile on your tire as well. A small profile is good for cornering and handleing, but not for towing. So you might want to check that as well. As far as 20" rim, my friend feels this size can not handle the stresses as well as a standard size rim. I am undecided. I would check with the mfg'r of the rim and see what they recommend. Also, make sure your tire pressure is higher. I have a 32' TT, which I pull with a 2500HD Diesel and I will run about 50-55 lbs in my tires. Low T.P. will cause sway. One more thing, tempature. I believe small profile tires will have higher temperature. This can lead to tire failure.
(2) Without seeing the four point equalizer system on your trailer / truck, I'm shooting in the dark here, but you need to have a sway bar. I'm assuming this system comes with one if it does, you may need to tighten the tension on it. It sounds like that you may still have a little too much tongue wieght as well. This can also be corrected somewhat with this system. So you may want try to tighten this up as well. Possibly check with your installer for help.
Anything you pull by the tongue will cause some pushing and bouncing. If I'm passing a cargo truck or being passed, my truck in trailer move and I have to compensate. I hope this has helped.