CBD has worked wonders for my sleep issues. I use a mix of vaping, broad-spectrum tinctures and full CBD flower extract, depending on what I'm in the mood for that day. The full CBD flower extract and broad-spectrum tincture do the most for me, though, particularly the extract.
I can't say it's had any effect on my waking C-PTSD apart from calming some of the severe anxiety, but for the insomnia, it's worked wonders. I hope it helps you too!