Someone several pages back said that your picture showed the hitch head to be centered on the trailer. I disagree! Your picture shows the hitch head (orange part) turned to the right (bottom in the picture). This means that the right hand strut bar is too short and the left one is too long. You need to adjust them very accurately so the distance from the edge of the orange hitch head to an identical point on the frame on each side is the same. In your case, I would measure each side from the top rear corner of the orange hitch head to the front mounting bolt of the tongue jack. Then you tighten the adjustment nut and lower the adjustment arm over the top of the strut. This will lock everything in place and the hitch head cannot move left or right.
The symptoms you described are consistent with the struts being either not adjusted correctly and/or loose and your picture confirms this. It has nothing to do with the spring bar adjustment whether by jacks or chains.
You MUST get the hitch head centered on the A-frame via those struts or the hitch will not operate the way it should. You do this without any truck hooked up and can even be done without the WD bars in place.
Hope this helps. :)
Barney