i love the reese set up we have. we used it on our travel trailer when we had it. 35 foot Coachman, bout 10,000-10,500 pounds. pulled it behind a 1/2 ton yukon xl because i didnt have my truck at that time. made the load sit dead level, the yukon didnt squat at all, and it has built in sway control. definitely a nice set up to have. as for setting the chains and the bars, we hooked the trailer to the truck, then jack the trailer back up so its level or a little above level, so the weight is off the the truck, or else its gonna put a lot of tension on it. once the chains and bars are set then jack it back down.
to unload the chains. reverse order, jack the trailer back up, and undo the load equilizing. because if you just try to undo it the bars will shoot straight down ebcause of all the tension on them. and then you can undo everything else.
this is straight from my dad, he's been towing travel trailers for 30+ years. always using weight distribuition and stuff like that. he said hes heard stories of people trying to unload the bars without taking the weight off the truck and the bars will snap down through there feet.