After switching to Whoopie slings to reduce weight I wanted a light toggle. First used Al tent stakes, then cut up some Al thick-walled kids arrows. Now I am using the dreaded Carbon-fiber arrow pieces. Would I use them If I hung on the edge of a cliff or below freezing?? Noooo, but 18" off the ground, Yes. No failures for me, guess I got my pieces (~6mm) from a quality source. Just like the DIY aspect and being able to carry "Extras" w/o too much weight.
Stormcrow says he just uses sticks found at campsite, to remove just break it.