It’d been so long since i’d done a thick yarn reroot that i forgot my own rules. Reroot the first line and parting with not just a wider needle fork size but a longer needle length – Place the strand against the head and root in just the top, pulling in the little tail so that you have single strands around the edges and double strands within.
Why not use the knot method? because thick fibres already stretch the vinyl, pushing in a knot or pulling wool back and forth could break it. With the tool method and a longer needle length, the tail goes inside.
The alternative is to root a tight hairline then go and snip out hidden strands and push in the stubs (like I did here) until it starts hanging better or root a not so tight hairline but paint in baby hairs (beyond my skillset)