colodak
Adventurer
5/16 would work, but if you are approaching your curb weight, you can easily push the limits of 5/16. 1.5x is a tad conservative, you should be looking at 2.5 -3x your loaded weight.
I was looking at a 10,000 lb rated rope that I may pull the trigger on then, it'll be almost 2x, but my winch is only 8K and I'm not planning to replace it anytime soon.