Does gynaglide bleed color like amsteel?
I haven't noticed any of the aforementioned flaking and I have used it for a packleash and tarp ridgeline for a season or two. Is it something you could notice by rubbing it between your hands?
As for figure9 usage, I'd be worried about the teeth chewing it up. I prefer prussiks and spliced deadeyes in the ends with microbiners.
Around the tree with the ends, clip onto the prussik midline and adjust. If you need less cordage because the trees are closer together, tie a marlinspike and put the biner through that, go around the tree and clip to the prussik midline and adjust. Much easier and lighter than figure9s IMHO.
As always HYOH/YMMV