This post should really be entitled "Do NOT Adjust Your Nib!!".
Having got the Demonstrator's Nib working with a change of ink I then went and spoiled everything.
I switched from the Monte Verde Purple to Caran D'Ache Amazon and found that the nib tines started 'ticking'.
This often happens with a new nib so, since I preferred the Caran ink, I decided to adjust the nib like I'd read about on the 'net.
All I had to do was ease the tines apart in small increments, testing the nib regularly as I went... So what happened? On the second 'easing' I bent one of the tines way too far and the nib stopped working.
I then spent ages trying to bend it back, but that's a lot harder thing to do, and unfortunately it bent in a different place, so I ended up with one kinked tine and one straight one.
The nib actually worked quite well, no ticking and good ink flow once started. But it needed a bit of encouragement to start flowing after a minute's pause in writing, and above all it looked horrible.
So I decided to send it back to Germany for a new nib. It's probably going to cost me in excess of £150.
So maybe nib adjustment is best left to the professionals...