Throwing out another option for stitching. I just use plain old #7/1-ounce pre-waxed sailmaker's twine. It's ends about 1mm like yours but being plain polyester would not be as strong (about 100 lbf test). I don't know of any reason why it would need to be rated cordage for this, though.
I prefer something waxed, it makes winding, stitching and tying easier. Plus with a quick heat pass seals and smooths the stitching. I'd probably send myself to a mental institution using my two left thumbs trying to tie UHMWPE into a tidy knot.
We had a good time yesterday. 8 in attendance. Did some demos and then made some loops.
Learned a lot. Its much harder to work old and wet winch line.
Once you understand how 12 strand hollow core dyneema and other brands of UHWMPE winch rope splices, not such a mystery.
Thank you @damon for hosting.