Make sure your snap-up brackets are firmly mounted to the trailer A frame if you are going to only use 4 links between the bars and the snap-up. During a turn, the bar ends move back and forth and with only 4 links under tension there could be a chance of sliding the snap-up bracket back and forth on the A frame. This could cause trouble with anything mounted there such as breakaway switch, propane tank mounts, etc. or the chain links themselves crashing into the snap-up brackets.
If 4 links feels better, then I would go back to 5 links and tilt the hitch head back towards the trailer a bit more to make up the loss of lift by adding back the chain link.
Barney
