Im gona guess what you have done is hang the light length ways along the bar instead of hanging so its across it.
Like I said, chain all four corners over the bar so its across not running in the same direction as the bar, then do the same with the other light.
Tie wraps work wonders.
Otherwise don't use the bar at all and use the top frame of the tent, that makes the lights easier to get level and stay level. . You just need long enough chain so you can lower or raise , again tie wraps will help raise and cut them off if you want to lower. I got some nice little hooks that work great for shortening the chain when I need to.
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