I have been experimenting with processing nettles after they have been drying for a week, or so, in the summer sun. AKA NO retting. Comparing it with the dew retted material the fibre seems very comparable, if not a bit stronger, and I love the colour. However I reckon it will be fugitive and fade. I have not spun this fibre yet, so can’t comment on its properties as a yarn.
On the measuring front, I got a total of 7 gr from 15 gram dried stuff, and fibre of various length from the green dried nettle skin bast. Some nice long line fibre, some medium length fibre some nice tow, some tow for other stuff (stuffing?) The stages roughly relate to my process: While getting the very long fibres from the dried nettles, shorter pieces come out, which I scrape later, and so on. Until I have short fibres left which need carding and then become a rolag.