I'm only 180, but I only use 1.75mm
Hmmm 1.75mm versus 1.8mm. Don't really see that it makes a bit of difference weight wise. Like AS said in 8-9 foot ridge line your looking at less than a gram difference in weight so the difference is tensil strength and color. As others have said the 450 pound rating on the lash it will be enough as long as you hang properly.