Thanks all for all replies… I did not manage to describe
accurately what I was looking for - my reference to Rio was not
I managed to get the pattern I wanted after some experiment - I
used a 1 mm wire which I twisted with a 0.4 mm - pulled through
drawplate down to 0.75 and then unwound the (earlier) 0.4 mm
wire. (perhaps one could use copper (Cu) as help wire instead of
sterling but I just needed a few so the “waste” is manageable)
Thanks again for all advice.